Indeed, but the art component (as in: relevance within the zeitgeist, social commentary, emotional message etc.) of these movements, while subversive, didn't hinge on the express illigality of the act itself.

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)