Last night I saw a pretty good spanish guitar concert in Barcelona (Manual Gonzalez). The crowd was mellow and relaxed but I noticed quite a few people holding up video cameras in their increasingly tired and wobbly hands for the entire show.

Why? The quality of the video is going to be horrible, it's a distraction from your enjoyment of the moment, and it's a distraction to other people too. And are you seriously going to sit down later and watch it? Odds are very, very low.