[kokey]

I think theoretically you can make it quite good, but it's not going to be a simple task and you probably can't rely on purely the fans' recording. I think the best way would be to modulate them together based on a weighting depending on position or distance away from where the music is coming from, also discarding distorted recordings etc. That said, you probably only want this lightly mixed in along with a good recording from the desk, all adjusted for the viewing angle.