I dont think its legal, maybe frowned upon, you see them every show you go to,

when i saw them at southampton i thought it was really funny, as they had stacks of tickets but the show wasnt sold out so im sure they ended up losing loads of cash, i cannot believe anybody would have bought them as you could have them booked them through official channels.

I can kind of understand using a tout if show is sold out and this is only way of getting a ticket but i believe most uk shows are still selling tickets so they may have a bad few weeks