Indeed, the old FTL game, Dungeon Master (an old RPG, its most direct modern successor-by-inspiration being Legend of Grimrock) put some copy-protection code in one of its sprites, where it hoped you wouldn't notice.
One part of it would repeatedly read one "weak" sector that had been incorrectly encoded on the disk in such a way that it would usually read inconsistently, and would crash the game with an obscure system error if it didn't read differently.
Cute, but kind of a problem when you have a much better quality floppy drive which read the weak sector consistently.
