In graffiti, a writer crosses out or paints over another writer's work. This is often done to declare that one writer is more talented or more up than the one being crossed-out. Good graff crews do this to claim territory or beef with a toy crew. It's necessary.
Dumb Toy 1: I can't hit that wall!
Dumb Toy 2: Why?
Dumb Toy 1: Because I'm a toy and someone will cross-out my name!