I'm a volunteer on a project there - going back tomorrow and the next day. It's a lot of fun - I've really enjoyed myself and met a lot of very awesome people. (It also helps that my husband keeps asking if I want to buy more stuff
It isn't that photos aren't allowed, it's that only some photos are allowed, and there are restrictions. Lots of booth owners don't want photos taken of their booths (you should see all the signs), and certain walls of the show aren't to be photographed. Moreover, if you take photos, there are specific rules you're supposed to follow regarding where to post them (You can't post them to a site that freely allows products to be made with the photos, for example.)