Alphonse mucha style graffiti

Not entirely true, because a blank wall serves no purpose like a phone screen does. It's just blank, ugly to look at, and boring. If I owned that building and someone made that without my consent, I'd hunt them down to pay them, not prosecute them.

Yeah, but you don't know if everyone would be so appreciative. You can't just assume that everyone would like your art, or that they are wrong if they want their property to be blank. If they wanted it painted, they'd hire someone to do it.

While both parties have no right to force their artistic choices upon one another, the owner of the said property gets the final decision on how or whether it will be painted.