Harry Potter: Wizards Unite/Headscratchers

Let's talk potion ingredients.

 * I can understand coming across magical plants, even in muggle areas. But who the hell is going around gutting dragons, newts, re'ems, armadillos, and other creatures and just scattering piles (or puddles) of their assorted body parts or fluids hither and yon?  Who's dropping bottles of honeywater and packages of butterscotch everywhere?