Unfortunately I think this was one of those knee-jerk reactions to quads and we are just lucky they haven't popped up elsewhere YET. Just like flying anywhere else there are plenty of reasons and places not to fly because it is unsafe. So if that is ever the case, just don't. I fly in the parks around NY with no issues and the blessings of all of the Rangers. It depends how many they see really. The original issue was that people were complaining that they could not go to a place like the Grand Canyon without seeing quads all day and it took away from the beauty. Whatever, we should be able to grasp that I suppose. However if I am going to a place where there are few people, I always bring mine and usually talk to the Rangers at some point (usually to tell them where they can find the footage). If you are safe and avoid the "tourist" national parks, I think you are more likely to find Rangers who like them or do not care either way.