Ah hah! Now _that's_ a conundrum... How can it be grafitti if it's not subversive? Grafitti as art would vanish in a puff of logic.
Grafitti is beautiful vandalism. Paradoxical, controversial, illigal yet defensible, vexing and captivating at the same time. Under the protection of the law, only half of these remain, leaving grafitti with the artistic content of the common tattoo. Illigal, controversial and vexing now replaced with vulgar, crass and stupefying.
(not to put down tattoos as an artistic medium, i'm just saying nobody's impressed with your sick sleeve, George)