A character makes up an Accidentally Accurate place or event as an excuse for not doing something
Do We Have This One? or can it be lumped with Accidentally Accurate? (Accidentally Accurate seems to be more unintentional on the part of the writers, this is unitintentional in-universe.) Alice keeps pressuring Bob to go to her piano recital, but Bob really doesn't want to go. Flustered, Bob tells her that he can't go to the recital because The International Flea Circus is in town that night. Alice knows he is lying not because an International Flea Circus sounds ridiculous, but because she is a big fan of the circus and knows that it isn't due in town for another six months. Accidentally Valid Excuse is when a character makes something up on the fly, usually a lie to distance themself from a person who annoyes them, but as it turns out they are Accidentally Accurate and the thing they assumed they just made up actually does exist. Closely related to Accidental Truth.