I think they're paranoid about new digital cameras that have limited MPEG/QuickTime features. Yes, my camera is capable of taking up to 2 minutes of video at a time (with sound), but it's hardly worth it. It's really only good for posting on a website and the image gets choppy, too. Also, banning spectator still-cameras is another way to make sure that the photographer at the comp gets some exclusive business. This is fine if he takes pictures of you, but like I said, I like to take pictures of other people so I can enjoy them myself.
"Do or do not, there is no try," Yoda, Episode V