Being one of those, I do have to say that we were up until about 2 or 3 the previous night getting setup for the event.  I personally had been up since 4:30 am on friday prior to setting up.  I can understand teh 8 or 10 people who did setup trying to get some shut eye.

As for others, its personal choice.  We provide the safe haven, power, parking, etc and how others choose to use it is up to them.

Yes, I know i stayed until there were like 4 people playing and I would have stayed longer but i had to take 2 people home and one was bugging me to go.  

I was playing a 32person bf2 map with one other person having a blast just doing the helicopter duel with them.