What if I'm not skilled enough to paint it back to how it was? Or don't want to break the law. Or some other barrier. My point is that if given equal rights, it isn't clear cut if you should paint at all. For example, on dedicated graffiti walls the situation is different since people generally agree how they should be used. Sure, one way to solve a conflict is to let everyone do what they want and see what happens, but it's just a version of "might makes right", imo.