So, speaking for SG 45 (and based on the videos I've seen of previous events), it's held in the DMZ, and it's more of a hyperball sort of setup. No airball.
(of course, the format may change for 47, but I wouldn't think so)
You gas up the marker, put on the mask, and walk onto the field. It doesn't matter that you failed a test, your girlfriend broke up with you the night before, or that you just had a bad day at work. This is your heaven on earth. Live it and play it as if there was no tomorrow.
(stolen with permission from theblackoutsavage)