The goal of this application would be to keep all those cell phones in peoples pockets during the concert and then to deliver a customized video clip to the person who got 'rained on'.
Why? What's the problem with taking out your cellphone during a concert? Why do you want to keep people from using it?
It's not the talking on the cellphone, it's the people holding up a cheap cell phone camera and actually trying to record the concert all at the same time. They basically end up with barely viewable recordings and they are not even in the video.
Again, what's your problem if my recording is crappy? Why does it affect you? Are you trying to “save” those people?