Not Cheating Unless You Get Caught

Rules are made to be broken, and that goes double for these rules.

Basically, the protagonists are given rules which are less instructions for keeping order and safety, and more a Secret Test Of Sneakiness. It's understood by all parties that the rule is not to be followed, and the only question is whether you can break it without getting caught.

This sometimes takes the form of an admonishment not to cheat on an upcoming game/test/whatever, which comes so out-of-the-blue that it can only be interpreted as an encouragement to cheat. A subtrope of Family Unfriendly Aesop. Compare Could Say It But. Take it further and you realize Real Life history is Writtenbythe Winners.

Compare Can't You Read The Sign. And sometimes the villain in What You Are in The Dark, or the foolhardly fellow teenager in Youth Is Wasted On the Dumb urges this trope to encourage something actually wrong.

Anime and Manga

 * In Death Note, Light Yagami claims that if Kira is caught, he's evil. However, if he isn't, he is justice.
 * In the third chapter of Fullmetal Alchemist, Ed transmutes waste into gold, claiming that: "If we don't get caught, we won't get caught." Immediately afterward, he subverts this by reversing the transmutation.
 * In a very early Naruto episode, during the Chunin exams the ninjas-in-training are given a difficult written test with the unusual rule that they cannot be caught cheating more than four times. So, needless to say, all of the skilled students discreetly use their ninja skills to do so without getting caught. Which was, of course, the entire point. (They would have to pass anyway--a few students were plants that actually had correct answers, so copying them was the goal--but it was just a Hidden Purpose Test.)
 * This is further complicated by the idea of teamwork being thrown into the mix. If one person in the squad failed or got caught five times, the whole squad failed. If one person got none of them right (the questions were intended to be too hard for regular genin to be answered), the rest of the squad also failed.
 * Earlier in Soul Eater, Black*Star tries to peep on Tsubaki while she's bathing, he being who he is, yells and gets a shuriken in the forehead. The thing is Tsubaki wasn't mad at him spying her but at him not being able to conceal his presence.
 * D'arby the Gambler, user of the Osiris Stand in Jo Jos Bizarre Adventure, has this as his motto. For example, it's not his fault that Polnareff didn't know that, when they were betting on what meat a cat would eat first, the cat belonged to D'arby (and thus D'arby could choose which piece would be eaten).
 * The first rule of the Games Club in Higurashi no Naku Koro Ni: Win at all costs. Including using marked cards, bribing your opponents, pulling a Twin Switch...
 * The Legend of Koizumi. It's practically understood that cheating is part of the game as long as you don't get caught. And sometimes, it's still not considered cheating even if you do get caught if you do it in an audacious enough manner, like when Koizumi's effort in cheating.
 * Getting caught, however, can be fatal
 * Toriko's Gourmet Casino arc lives and dies on this trope. Coco's future-seeing abilities allow him to effortlessly win practically all of the casino's games. Livebearer, the arc's Big Bad, on the other hand, runs a game that is designed to give him every advantage he can think of.
 * Toriko's Gourmet Casino arc lives and dies on this trope. Coco's future-seeing abilities allow him to effortlessly win practically all of the casino's games. Livebearer, the arc's Big Bad, on the other hand, runs a game that is designed to give him every advantage he can think of.

Card Games

 * Unhinged, one of the joke sets for Magic the Gathering has a card called Cheatyface, which you're allowed to put into play for free as long as your opponent doesn't catch you doing it.
 * Particularly amusing when paired with Ashnod's Coupon (Target player gets you target drink). While they're in the kitchen, there is nothing stopping you from putting all 49 copies of the card you possess into play.
 * A flare in the original version of Cosmic Encounter gives its owner a similar power: if you have the filch card in your hand, you can filch cards from the draw deck or discard pile, and reclaim your own destroyed ships, as long as nobody sees you do it. If you're caught, however, you have to put what you stole back, and an extra ship of yours is destroyed. The most recent remake includes this card as an optional variant.
 * Steve Jackson Games' conspiracy-theory themed card game Illuminati has a set of "cheating" rules in which almost anything goes (e.g. stealing money from the bank, misstating the powers of your cards, etc) as long as you don't get caught. (If you do get caught, the only penalty is that you have to undo that specific cheating attempt.) It is recommended that you play this version of the game only with "very good friends or people you will never see again."
 * The entire premise of the card game known varyingly as Cheat, BS, or I Doubt It. You put down a certain number of cards in a group (such as two aces or three kings) into a pile while everyone else would watch you and either leave you be or call you out for cheating. The idea is to get rid of all your cards in your hand before anyone else does, and it is possible to cheat by dropping down cards you didn't call (such as saying you dropped two aces when they were really a 6 and a 9). If you are called out while you cheat, you have to pick up the whole pile for cheating, but if you weren't cheating when they called you out, they have to pick the pile up. It is very much possible to cheat without anyone calling you out on it so long as you don't make it painfully obvious (such as dropping 5 queens, or a card someone else has all 4 of), and in fact, required since passing is not allowed.
 * People are divided as to whether or not you are allowed to cheat otherwise. One school of thought is that since it's the name of the game, you should cheat as much as possible by hiding cards or playing more cards than you declare so you can't be caught cheating. The other school allows only cheating in the predefined method.
 * This is an explicit rule in Munchkin. It's to be expected in a game about munchkining.
 * In general, any card game that has a specific rule against cheating is really saying this trope. To catch someone cheating, you must accurately describe their cheating action, or be penalized yourself for a false accusation.
 * In Euchre, there is a significant advantage to being the dealer. Normally, the deal passes to the left after each hand, but the dealer's partner (or in cutthroat, any player) may gather the cards and attempt to shuffle and deal. If they're caught before they finish, they have to pass the deck to the proper dealer, but once the deal is complete, the hand must be played.
 * In UNO!, you are not allowed to play a Wild Draw Four card unless you have no cards in your hand of the color of the faceup card on the table. Attempt to do so, and you won't be penalized, unless another player calls you for it. (Which they sometimes do just to look at your hand.) Even better, the challenger can be penalized for an improper challenge.

Film
"Razul: Gotcha!
 * In the movie Spies Like Us one of the two "heroes" (to use the term loosely) managed to pressure the other into helping him cheat on their government promotion tests, through good, old-fashioned Chevy Chase-style chuztpah. When discovered, in order to cover themselves, they worked together by reflex to cover each other. The CIA test givers were so impressed that they gave them an immediate promotion to field agents. (Of course, this was a plot to throw expendable agents into the field as a diversion for more nefarious activities ... but the trope connection is solid.)
 * In Star Trek II, Kirk reveals that he rigged the Kobayashi Maru test to make the scenario winnable... and got a commendation for "original thinking."
 * In the 2009 film the alternate Kirk was court-martialed. If the plot had not intervened, it is very possible he would have been expelled, which is standard practice for modern academic institutions. Presumably something similar happened to Kirk-Prime, but if he was being a bit less of an ass about the whole thing (and if he had some powerful friends), he might have gotten away with it.
 * The difference may have been due to the manner in which they cheated. Alternate-Kirk simply disabled the shields of the enemy vessels and destroyed them, while Kirk-Prime reprogrammed the enemy's behavior to respect the reputation he intended to build as captain such that they would allow him to proceed unmolested. So while Alternate-Kirk cheated in a way that he could plausibly have hidden and gotten away with entirely if not for the fact that the game was Unwinnable, Kirk-Prime took Refuge in Audacity.
 * In Back to School, Derek (Robert Downey Jr.), best friend of the main character's son, uses sunlight reflected from a mirror, and then an air horn, to distract divers from the opposing dive team, preventing them from making good dives so that his friend can win.
 * In Ski School, the "good guys" Ski team must beat the Big Bad and other innocent bystander competitors to stay on the slopes, so they pull shenanigans like pouring oil on the snow to make their competitors slip and fall, or have buxom ladies flash passing skiers to make their competitors slip and fall. High fives all around.
 * In Aladdin, the title character remarks about his stealing food from the marketplace, "you're only in trouble if you get caught!". Which segues into this little exchange:

Aladdin: I'm in trouble."


 * Pirates of the Caribbean: The Pirate Code is really more a set of "guidelines", or "suggestions." At least they are on the open seas; not so much when Captain Teague, Keeper of the Code is in the room with a loaded gun. Still some room for... Liberal interpretation, of course.

Literature
"Moody: Cheating's a traditional part of the Triwizard Tournament and always has been. I've been telling Dumbledore from the start, he can be as high-minded as he likes, but you can bet old Karkaroff and Maxime won't be. They want to win. They want to beat Dumbledore. They'd like to prove he's only human."
 * In the Discworld Assassins' Guild, student assassins are given a list of places which are "out of bounds." This is defined not as places they can't go, but as places they can't be seen by a master, which should give them lots of practice at the skills required by Guild members.
 * It's also considered a pass if you assassinate your examiner - though considering he's an experienced assassin himself, you're advised to be very sure you will succeed before trying it.
 * In Tamora Pierce's Tortall Universe books, Pages and Squires train at the Palace - and one of the rules is "Don't get into fights". Of course, pages and squires fight all the time and are caught, but the traditional excuse is "I fell down". When the protagonist is being bullied on a regular basis and learns a less honourable style of fighting to beat the bully, they are read the riot act. Except not, because their teacher is secretly glad the bully was dealt with and the protagonist reflects on this rule as they are being told off.
 * In Harry Potter's Triwizard Tournament cheating is a more or less accepted tradition that every single side engages in. When Harry (who was entered into it against his will) tells Cedric they're up against dragons in the first task, Moody doesn't bat an eye.

""If we're not stooping, what do you call that shell game with the Vortugalovs and the uterine replicator?" Ivan demanded indignantly.
 * In Larry Niven's Known Space stories, a Belter (asteroid belt miner) who's never been busted for smuggling will get looked down upon by his peers - because it might mean he's never tried.
 * This was pretty much Miles Vorkosigan's modus operandi, until Memory when he got caught, and it blew up in his face. He tried it again when courting Ekaterin in A Civil Campaign, and it blew up in his face again.
 * And lampshaded in A Civil Campaign:

"A piece of wholly unexpected good fortune. None of us here had anything to do with it," Miles replied tranquilly.

"So it's not a dirty trick if it's untraceable?"

"Correct, Ivan. You learn fast. Grandfather would have been...suprised.""


 * In The Hunger Games, it is technically illegal to train children to participate in the Games and have them volunteer to take the place of whoever gets chosen by lottery. Regardless, the tributes from Districts 1, 2, and 4 are always what are called "Career Tributes". The Capitol seems to ignore this because it makes for a more entertaining show.
 * In Raymond Feist and Janny Wurts' Empire trilogy, betrayal and assassination among rivals in the major Houses is almost never punished by the law unless the perpetrator was crass enough to be obvious about it. And being able to engineer a rival's demise by exploiting law and custom rather than just ignoring it will earn you the quiet admiration of your peers.
 * The Drow (see Tabletop Games below) deserve a mention here as well, since R.A. Salvatore's Drizzt books did a lot to codify that picture of their society.

Live Action TV
"Godber: I mean, we're all here for different reasons, aren't we?
 * Al Bundy says as much in an episode of Married With Children where Al enters himself in an athletic competition for senior citizens. When he's standing victoriously on the podium and holding his medals, he says, "It's only cheating if you get caught."
 * Porridge basically is this trope, with Fletcher delivering lines like:

Fletcher: With respect, Godber, we are all here for the same reason. ... We got caught."


 * The trope name is spoken almost verbatim in Andromeda by Gaheris Rhade to Hunt in a Flash Back when Dylan catches him cheating at Go. Rhade is visibly confused as to why Dylan is angry at him. Being a Nietzschean, he naturally assumes that everyone behaves that way, if they want to survive.
 * In a Warehouse 13 episode, Artie plays a game of Battleship with an AI that has taken over the warehouse. He wins by not actually putting any ships on the board. This is used to prove a point to the AI that it is merely an incomplete version of its creator, who is a master cheater.
 * Theoretically, anything a team on Scrapheap Challenge/Junkyard Wars brings back to their lot is theirs for keeps. Yeah, right ... unless the other team steals it, in which case the hosts and thieves have a laugh at the victimized team's expense.
 * Jeff Winger on Community runs basically the entire spectrum of amorality tropes. One of the more Egregious examples is him creating fake classes to earn credits.

Music

 * "Tweeter and the Monkey Man", by the Traveling Wilburys. "Janet told him many times, 'It was * you* to * me* who taught in Jersey everything's legal as long as you don't get caught."
 * Tool's song "Jerk Off" summarizes the mentality explicitly: "If consequences dictate our course of action then it doesnt matter what's right, it's only wrong if you get caught"

Professional Wrestling

 * Virtually half of the way the whole show works, especially with the manager or tag team partner getting in a few shots while the ref's back is turned. Mostly done by heels, but sometimes by faces against a heel who's really gone out of his way to deserve to be Hoist By His Own Petard. Though in The Nineties it became increasingly common for Darker and Edgier faces to consistently use "heel" tactics like this as well.
 * Wrestlers can even do this by themselves if they can get the referee to turn his back. I mean, sure, the ref looked away for two seconds and now one of the wrestlers is lying unconscious on the mat, with a steel chair next to him - but he didn't SEE it, so he can't just go blaming the only other guy in the ring, can he?
 * Eddie Guerrero lampshaded it ("I Lie, I Cheat, I Steal"), and later in his career took to inverting it (e.g. by hitting the mat with a steel chair, tossing it to his opponent, then playing dead and winning by DQ, which worked even though normally refs only call a DQ if they see the illegal hit).
 * Eddie won his very last match in exactly this manner.
 * In one Royal Rumble match, Stone Cold Steve Austin, after being eliminated by Bret "the Hitman" Hart while the Easily Distracted Referee wasn't looking, jumped back into the ring quickly and cleared the ring to win the Rumble.
 * A subversion sometimes happens in the form of the "Dusty Finish", named after Dusty Rhodes who used to book this sort of finish all the time. In this case, the trope is played straight until the match is finished and one wrestler (often the face) is declared the winner, only for a second referee to come out and inform the first referee that the face did something to cause a disqualfication (usually throwing the heel over the top rope, which was illegal at the time), causing that referee to reverse the decision. Because the face is usually on the losing end of the Dusty Finish, this practice is widely hated among wrestling fans. The most infamous example occurred in the AWA, when Hulk Hogan apparently won the title from Nick Bockwinkel, only for AWA president Stanley Blackburn to personally reverse the decision because Hogan threw Bockwinkel over the top rope. The fans nearly rioted as a result, Hogan left the AWA for Vince McMahon's WWF, and the rest is history.
 * One laughable subversion of this was at Starcade 1999 in WCW, during a 'Master of the Powerbomb' match between Kevin Nash and Sid Vicious. In the storyline, the match could only be won by, surprisingly, Powerbombing one's opponent. After the referee had been bumped, Vicious had powerbombed Nash and various outside interference had muddied the waters, Nash attempted to powerbomb Vicious, but for whatever reason was unable to and simply left Vicious laying in the ring. When the referee finally awakened, Nash told the official 'I stuck him!' The referee, amazingly, believed him (!) and awarded the match to Nash.

Tabletop Games

 * One of the scenario ideas in the GURPS setting book GURPS IOU, set in a very peculiar university, involves the final exam for the Advanced Cheating class. The questions are just random obscure trivia; the actual test is finding a good way to cheat in it. If you get caught, you fail. If you don't even try to cheat, you'll be expelled for "terminal cluelessness."
 * The difficulty to this being, of course, proving that someone did not cheat.
 * Drow from Dungeons & Dragons. Their entire legal system is based around this trope. As an example, in the city of Menzoberranzan if a Drow Noble House wants to eliminate another Noble House they must do it in a way that leaves no member of the eliminated house alive, since only the attacked house has the right of accusation against the attacking house, and are the only ones allowed to witness. Anyone else who happens to see the attack are merely "spectators." If even one member of the attacked house is alive to accuse the attackers, the attacking family will, according to the law, be eradicated. If no one is left alive to witness, everyone will act as if the now deceased house never existed in the first place, except for vaguely praising the attackers for a successful raid.
 * In Drow Tales, one of the rules of the School of Magic is "If you attack another student, you must kill and dispose of the body."
 * After Drizz't Do'Urden abandoned his House and that House subsequently lost the favor of Lolth, it was annihilated by House Baenre, the First House of Menzoberranzan. However, not only Drizz't, but his brother Dinin and sister Vierna survived the massacre, being taken in by the Bregan Daerthe mercenaries. When Dinin asks Jarlaxle if he'd rescued them because of their claim against the Baenre, Jarlaxle basically tells him, "Pssh. Yeah, like that'll ever happen".
 * So House Baerne is cheating the rule that says under what circumstances it's permissible to cheat?
 * Presumably, the other seven would have a perfect pretext to unite and get rid of Baenre if survivors brought it before the Council. The hard part is to live long enough to do it, of course, and preferably stay alive after the deed as well. Another issue is whether one remains a noble and can make a claim if officially accepted as a merchant clan or mercenary company member, like Jarlaxle (Baenre himself). After all, his stand-in Kimmuriel Oblodra is the last from a punished House, but isn't targeted more than anyone in his position would be.
 * At that point in time, House Baenre is the First House because it's easily more powerful than any one (actually quite likely two and possibly more) of its rival Houses and enjoys the full favor of Lolth. Drow being drow, an alliance powerful enough to unseat it on such a flimsy pretext just isn't going to happen...and so history simply gets Writtenbythe Winners once again.
 * Paranoia officially prohibits players from even knowing the rules. It then acknowledges that the players will read them anyway. To provide a "don't get caught" aspect, summary execution of a character is recommended if the player tries to Metagame (although with five backup clones, this is more a warning than a bolt of purple lightning).
 * That information was outside your security clearance. Please report for termination. Have a pleasant daycycle. The Computer Is Your Friend.
 * On the other hand, if the rulebook also includes a pre-written mission, then the prohibition on players reading the mission is clearly labeled "no, really, this time we really mean it!"
 * One of the lessons taught to children by playing Monopoly is that you only have to pay rent if the person who owns the property realizes you're there.
 * If a non-word is played in Scrabble, but the next player takes their turn before anyone notices, the word stands.
 * Actively part of the fluff in Blood Bowl. Refs can be bribed to not call illegal play, may not see the illegal play, or may be too afraid of the crowd's reaction to call anything.
 * The Barathi society of Swashbucklers Of The 7 Skies has a strong vein of this, matched with extreme legalism (they invented lawyers) and the cultural practice of Vendetta. If you get away with it, it's considered a brilliant piece of politicking to be praised and emulated whenever possible... but if you are caught, then there's a fair chance you and everyone you love will "regrettably drown" well away from water.

Video Games

 * Academagia has a lot of Byzantine rules that amount to "you're not allowed to go anywhere or do anything except attend class and stay in your room the rest of the time when not at an Academy-approved activity." You're expected to sneak out and take a walk in the gardens to learn more about the world now and then, but if you get caught, you'll get detention.
 * Space Quest V: At the very beginning of the game, you have to get a perfect score on a multiple choice exam of unusual questions. Luckily, you can look at another test-taker's answers as long as you don't let the resident anti-cheating robot see you.
 * It's 100% possible to finish the quiz on your own (since Deus Ex Machina ends up giving you a higher score than is technically possible). However, if you cheat off the guy who's not the brainiac, your previously poor academic performance gets you kicked out of the academy immediately.
 * Additionally, even if you have all the correct answers, if you do not cheat once during the test, you get a game over when the test is over - the same game over for having incorrect answers.
 * Sounds like a bug that isn't present in my copy of the game. The questions are easy enough to answer yourself without cheating and still pass in-game.
 * In Breath of Fire III, there's a minigame where you have to train a scrawny man's skills so he can beat a musclehead in a duel. You get disqualified only if anyone sees you interfere with the fight itself. Trick is that Zig only looks away after a Critical Hit, so you can't just rush in after one session of training.
 * In Americas Army 3, during Combat Lifesaving training, you are specifically told several times that no cheating or talking is allowed. This doesn't stop you at all from asking the student beside you for answers to the test and getting a perfect score.

Webcomics
"Eglamore: We have rules for a reason. For your safety. And if you're going to break them, you should try harder to not get caught."
 * In Gunnerkrigg Court, Eglamore's advice to Antimony was not exactly what one'd expect from the teacher grounding a student. Annie initially criticizes this advice, but she has no trouble following it later. Of course, his company in their time used to do the same...


 * Generally the Court uses visible and mediocre security measures which kids can and regularly do hack, jam or bypass on their inevitable forays into the Court. While quietly employing a very advanced, undetectable and unexpected in its work tracking system (of course, this ran smoothly only until one young Mad Scientist discovered it while hacking around their network) and/or beings that look innocuous, but are more than capable of stopping most troubles into which students could possibly get.
 * A number of strongly forbidden behaviors in Girl Genius are tacitly acknowledged to the point that the real crime seems to be doing them sloppily, such as students spying on Castle Wulfenbach, Jägers sneaking into Mechanicsburg (where they're forbidden until the Heterodyne gets the castle under control), and nobles being resurrected (which formally results in loss of all titles and permanent ineligibility).
 * In Sluggy Freelance Torg is forced into a parody of the Tri-Wizard Tournament from Harry Potter, despite having no magical ability whatsoever. So, when faced with the task of defeating a giant, sword-wielding chicken, he interprets the rule saying "be resourceful and use the tools around you" to mean he can lift a magic-user out of the stands, point her at the chicken, and let her kill it. And if that fails, he's still got Plan B, yelling, "Eat her! I'm old and stringy!"
 * Possibly a shout-out to Ranma One Half where spectators get used as improvised weapons during the Martial Arts Rythmic Gymnastics fight.
 * Several of the characters in Schlock Mercenary view all rules as these, including Captain Tagon. Petey, while generally benevolent, both loves underhanded methods himself and once managed to get Toughs off the hook without confronting human governments by eagerly agreeing they are less than law-abiding, but making them drop all charges because U.N.S. doesn't want him to publish as part of the extradition process the very facts they tried to cover up.
 * Megatokyo: Trying to convince himself.

Western Animation

 * South Park: Eric Cartman once posed as a teacher for a bunch of hooligan teens. Instead of teaching them all that normal stuff, he taught them to cheat at tests.
 * While dressed as Edward James Olmos in Stand and Deliver. "How do I reach these keeeds!?"
 * And to top it off, he continually referenced Bill Belichek and the 2007 Patriots, claiming that the moral of that situation was not "Don't cheat" - but rather "If you got to where you were by cheating, keep cheating!"
 * Megatron once tried doing this against Optimus Prime in an episode of Transformers Generation One; he challenges Optimus to a duel of honor, with the loser exiling themselves, only to use a machine to transfer his underlings' powers into him and sending the Constructicons out to destroy the Autobots' computer, so it wouldn't be able to warn them of the duplicity. It doesn't work, in the end, but Optimus did completely miss the obvious signs of cheating on Megs' part during the battle.

Real Life

 * Water Polo is rife with this behavior.
 * Sparta liked this trope:
 * As a rite of passage The Spartan Way, each Spartan boy would be denied enough food to survive, forcing them to steal from the Helots. Stealing was still illegal, however, so if the boy was careless enough to get caught, he would be punished mercilessly.
 * For soldiers, the same applied to having sex with your wife - the men lived together in barracks and were "forbidden" to go home. The idea was that if you had to break the rules to sleep with your wife, you'd take it a lot more seriously. Sparta always needed more sons.
 * Truth in Television, for the hiring test for a certain spy agency.
 * Two of the unwritten rules for special forces (read: commando) groups are "if you ain't cheating, you ain't trying", and "if you're caught cheating, maybe you're not special forces material."
 * "If you ain't cheating, you ain't trying" is also a commonly acknowledged "rule" in NASCAR racing.
 * A famous baseball player commenting, "If you're not cheating, you're not trying hard enough". It certainly seems to be a time-honored tradition in sports...
 * In the year 1000 the nation of Iceland officially converted to Christendom. While the transition was smooth and surprisingly bloodless, worshiping the old gods was still allowed as long as it was done in secret.
 * Many religions established footholds and spread like wildfire only after authorities tried to snuff them out. A number of religious philosophers have actually longed for 'fire' to re-forge their groups' beliefs during periods of prosperity as peace tends to foster complacency and legalism.
 * Any school exam under the honor system.
 * Some public transportation in Europe runs by an honor code where you get on a bus or train under the assumption you already payed your fare. Of course there's the risk that an inspector may ask to see your ticket...
 * The Washington Naval Conference laid down strict limitations on the construction of warships, with the idea of preventing an out-and-out, ruinously expensive battleship arms race (similar to the one Britain and Germany engaged in prior to World War I). Of course, the nations that didn't wiggle through the loopholes (it's 10,000 tons and it carries 15 fast-firing main guns, but it's still classified as an innocent-sounding and unrestricted "light cruiser" just because the guns are six-inchers) decided "screw tonnage limitations!" and started laying down ships that exceeded the tonnage limitations by 25 to 40%. Special mention goes to the Japanese, who categorically denied Western rumors that they were building forty- to fifty-thousand ton battleships (when the limit was 35,000 tons). The battleships in question turned out to be the Yamato class, which weighed in at 65,000 tons. Nobody knew their exact weight until after World War II.
 * Japan was also building 8-inch gun turrets that didn't have ships to go with them, ostensibly as spare parts for their heavy cruisers. In actuality, those 15-gun light cruisers were always intended to have their 6-inchers replaced by 8-inchers as soon as Japan could get away with it. And those cruisers were also already weighing in at 12,500 tons rather than the official 10,000.
 * Similarly, the Italians relied heavily on outright cheating to bypass the treaty, but turned out to just not be as good at it as the Japanese. Prior to World War II, other nations' naval officials were astonished at how Italy managed to built cruisers that were a good 50% faster than comparable ships of other nations. It turned out, the way Italy managed that was to send the ships on their shakedown cruises without carrying such minor items as gun turrets, thus making them come in (barely) below the 10,000 ton limit. In actual combat conditions, the added weight from actually carrying weapons meant that Italy's ships, far from the speed demons they seemed to be pre-war, were actually slower than their British and American counterparts.
 * Smuggling was notorious for this in the Early Modern era, to the point that the original "tea party" was in response a tariff cut putting American smugglers out of a job.
 * Not entirely accurate. Arguably the larger problem came from the tariff exemption granted to the East India Company, a corporation owned by the crown and nobility. Because their tea wasn't taxed, they could set up tea houses in the colonies that could undercut the Colonial tea houses and drive them out of business. While smugglers lost their jobs, they didn't generally live in the colonies full time... but the local business owners and their employees did, and their discontent lead to the Boston Tea Party. It is never the less a historical irony that the tea dumped into the harbor was dumped because it was not taxed.
 * Especially ironic that modern anti-tax activists named their movement after it.
 * Rules and laws in general are meaningless unless enforced. Breaking a rule, leaving no evidence that a rule was broken, and not getting caught in the act is as good as obeying that rule (unless, of course, the rule/law was put in place because of the long term concequences of breaking it. Or for your own safety.).
 * Examples are Third World countries where laws are often similar to those in developed nations, but since law enforcement tends to be weak/corrupt only a minority of offenders is arrested, sometimes selectively.
 * Two Words: Parking meters.