One irony is that you can't be sure their tickets are legit -- they do nothing to vet tickets for events they don't have official-marketplace status and control

One irony is that you can't be sure their tickets are legit -- they do nothing to vet tickets for events they don't have official-marketplace status and control the ticket codes. They even accept edited PDFs. All the guarantee says is that if the tickets are no good, they can (their choice) either (a) give you different tickets that they call "as good or better" or (b) just refund your money, and you're SOL (too bad if you've already spent hundreds to thousands on travel and such). They will do (a) only if they have cheaper inventory (again, unvetted, so you face the entry-denial risk all over again) still available on the site. This strategy usually works, as 90+% of events experience price drops as the event nears.