Across the boards, HOB are anti picture, anti taping.... of course if the band allows it and is willing to fight to let you have it, it's all good.
With that said, I snuck in a 75-200 mm lens and camera etc to the BTE HOB show in Chicago i think 2 1/2 years ago, had foundation room, etc, and never got busted.
You don't want to leave anything into the foundation room that I can tell, but I was really .. really.... REALLY .... drunk (let's just say after the show it took me almost 3 hours to get to Naperville from the HOB driving.).