I own loads of them, most of my shirts I've ever owned are music related, but I'd never buy a shirt of an artist I have either little or no interest in. You've mentioned GNR, but Nirvana t-shirts are really popular too with these idiots (which annoys me as I own a couple Nirvana shirts). I bet if you asked most of these people who Nirvana are, they'd probably think they still play...
Anyone who is watching, here's the failed proposal (I hope - not good at this): [video]http://m.youtube.com/watch?v=UtPkxzHKLpk[/video]