Well, all of the people with photo or video cameras at that particular event (and most of the things I attend) were doing so as a favor to the bands. Bands like photo and video evidence of their concerts! It's great for promotion among other things.
I do, however, agree with you when it comes to teenagers taking portable point-and-shoot cameras everywhere and taking pictures of themselves doing absolutely nothing so that they can go on Facebook and everyone can see how their friends were doing absolutely nothing.