I think the rule should be you can put your camera in the air for a grand total of 45 (I'm willing to compromise and say 25-30 )seconds throughout the entire show.
How would you monitor or enforce that for a few thousand people?
As a fan, I'm of the... I really don't care about this either way, view.
Obviously I was being a bit facetious. It should be a self imposed rule.
What hurts DT more, a guy who pays the ticket and films the entire show and puts it on youtube or that guy not being there at all and no ticket purchase? Honest question.
It's apples and oranges but I will play devil's advocate.
If someone films a show with a crappy camera and puts it on youtube, people might say the band's performance is lacking and not take into consideration that a cell phone almost never adequately captures the quality of the band's performance. This could lead to more people choosing to sit out from seeing the show.
This goes along with the downloading question that was discussed a while back. It wasn't a "fun" discussion so I don't want to rehash it but even though I generally feel downloading isn't a big deal, I do think a band has a right to present a product they want to (which is why I never download, legally or illegally because I feel you should have the full product in front of you with artwork, lyrics, etc).
I do watch youtube videos occasionally so perhaps it is a bit hypocritical, but if I had to choose between a million cameras in the air disrupting a performance and getting to see the shitty upload 2 hours later from half way across the world or going back to the dark ages of 2003 when we didn't have that ability and generally had to be in the moment at the concert, I would choose the latter.
Sure, some people might be encouraged to spend the money after seeing a youtube vid and others might be discouraged. Just like with downloading, it sometimes benefits a band and sometimes hurts them. Ultimately consider two things: What does the band want and what do the people around you want? In other words, as James said at the last concert I saw them at, "We're not saying don't take a picture or get a 30 second video, but after you do, put that flippin' thing away and actually watch us in 3D" (paraphrased)