There are zero consequences for doing this kind of thing. In fact many times we have seen pictures posted of "acceptable artistic graffiti" on this very forum. None of it is legal and either you accept it or you don't. If people are accepting of any form of graffiti in public or on private property, then then this is where we are going to be. If they had done something "more creative and artistically acceptable" yet still illegal, then what? Oh and my taste is different than someone else's so who gets to decide what is acceptable to any degree? The loser in the picture may think it's art...so let them have their fun I guess.