Roley

To me its not about restricting 'other' commercial photography, it is about exhibitor's/friends in general having respect for the official people present. Even distributing quantities of images for free is going to greatly effect photographer's sales. After all, why would someone bother to buy a photo when they can get something similar for free?

I think its a different issue if people are there taking different kinds of photos to what the OP is taking, they could have any reason for doing this. If its not clashing I don't see the problem. If its clashing I see it as a big problem.