Mafia 84. Memorized it, turned it in, forgot it!

In short, it gives a huge advantage to the town.

Nevertheless, shouting "I'm peaceful" is allowed even when such a cry leads to immediate exposure (simply because there is only one peaceful role for every person shouting). A clear example: Arandor in game 77 ("I'm peaceful" = "I'm an idiot") or me in game 74 ("I'm peaceful" = "I'm Ivy"). :D