@browncoat - It's easy to say that people should be able to do whatever they like when it comes to filming, but that doesn't take into account all the issues it can cause with the greater world. Whether or not you believe Disney should be able to stop people from making commercial films on their property without permission, there are hundreds of people and their children at those parks at any given time, and they would all end up being included in a film against their will. If it's a horror film, or an adults only film, is it OK to include the public? I don't think many people would say yes.
And that's not getting into the safety concerns. Filming can be extremely dangerous and a lot of the laws that exist around it are there because people might otherwise be injured or killed. Indie filmmaking often has great value, but I wouldn't measure it against the lives of those making the films.