Usually the attraction of having us at an event is payment enough, however, some event coordinators don't see that. Also, on the flip side, we are just geeks in costumes that do this for fun
I remember hearing from the old dogs about the early days of fanexpo where we were like everyone else, changed in the parking lot and paid to get in the con. However, once the organizers saw the draw we brought, they quickly starting accomodating.
If it is an event you would like to attend, I would simply pay entrance and watch the organizers faces as they see you get swarmed for photos. I would guess you wouldn't be paying next year
My 2 cents