"...seriously how?" Cameras were snuck in by a boo koo load of people including myself. I read here that there was not advance notice of a "no camera" policy but signs were posted outside the venue. That said, with the volume of attendees and basically two individuals checking belongings and minimal pat downs, there were a lot of cameras and cell phones in the venue. It's really very simple actually.

I can't remember a concert I've attended in which cameras were allowed...so this was the norm for me.