The problem is that you need to link what's checked at the door with the online trail. If you only allowed people holding the band's CD to enter, that'd definitely work but it's just turning a different physical object into the ticket.

You could try to have a trusted third party verify ID and only allow registered accounts to participate in the resale market (Ticketmaster sells this service) but at that point the blockchain is, as usual, not adding anything other than overhead because the trust depends on that third-party and the venue's staff checking ID at the door (otherwise you'd find people on Craigslist paying people to register, get their ID checked, and letting the scalpers use their account).