A general term for this is a "copyright trap" [1]. Map makers for example often add small, fake features to be able to tell if another map was copied from their

A general term for this is a "copyright trap" [1]. Map makers for example often add small, fake features to be able to tell if another map was copied from theirs. [1] https://en.wikipedia.org/wiki/Fictitious_entry https://en.wikipedia.org/wiki/Fictitious_entry