I like to introduce and demo safety mechanics with relatively low stakes (e.g. X-ing a name, lining/veiling something everybody might automatically assume to be off-limits anyway, etc.) early in the games I play.
This game-tool-hybrid looks to be a smart and carefree way to get folks comfortable with using such mechanics to go deeper into the narrative, thereby experiencing that a story (and the fun you have telling/roleplaying it) can survive quite a bit of adaption (and might even become better for it) if you care to take into account the sensibilities of everyone participating.