At Ariel's, the Photopass photographer would not take my camera and would not let me stand where he was standing--so the pictures of my children with Ariel are from a totally different angle. I think it is because it isn't a real Photopass photographer, rather it is a photographer who takes pictures that they then print and bring to you at your seat to sell to you. Pretty darn annoying if you ask me!
Other than that there were no issues with using my own camera and other Photopass photographers in the park were always willing to use my camera as well as their camera.