Okay, so imagine this: So you've got a trans person who has changed their name on a personal level but has yet to get their name changed on a legal level. So an evil wizard or some such steals their birth certificate to learn their true name for a spell (cause when you're an evil wizard, just asking is out of the question). But when the spell is cast it doesn't work cause the name on the birth certificate isn't their real name, thus the very laws of magic and the universe itself accept them as valid.
