Anyone who is into graffiti (not trying to include myself in this, because I've never really gotten into it) must know Banksy, he's like a legend to the graffiti world. And I heard of him because of his outspoken political views, which got me to look at his work. Yes, it isn't technically stealing, but I think the whole point of the contest is to make a sick design on your own, rather than borrowing someone else's (although, for the record, I would probably buy your shirt if it won.)