Here's a video of Simple Plan with OSM http://youtu.be/7ory04vCihw will give you a good idea of the spirit of the venue.
Personally, I saw Adam Cohen there and the crowd was really quiet.
Last Mika concert I went to, crowd was really joyful but respectful and nothing happened. I expect the same at OSM.
Filming and photography is stricly forbidden by the hall.