Alibi

Alibi is the social permission a character gives you to act in ways you normally would not, because within the game it is the character doing it, not you.

When you play a character, the fiction gives you an alibi: the shared understanding that what happens in the game belongs to the character. That is what lets a shy person play a loud captain, or lets two friends play bitter rivals, without anyone taking it personally afterwards. A strong alibi helps people try things they would never do in everyday life, but it does not cover everything. It never excuses ignoring someone's real boundaries or the game's safety rules, and organisers can make the alibi stronger or weaker through how they write and brief the game.