All I can say is this...
If you really want to see a show, no matter how popular the band may or may not be, just buy the tickets in advance. That way you'll never regret anything.
Guessing how popular a band is, how together their fans are, whether people are willing to pay that much to see them, etc. is irrelevant-- it's a game you'll never win.
The other plus is that you don't have to come early, wait in line, and hope. You can show up at 10pm and know you're in.