I'm getting so leery of the 400 ft limit. Let me use an example:
El Capitan in Yosemite National Park is 7,569 feet high, and has a nice, steep vertical plane to it. If I were to stand at the top and throw an airplane off of the top, as soon as it clears the edge, it's now over 7,000 feet high to the ground, and, under that 400 ft AGL, could net me huge fines.
I know, I know - it's illegal to fly in a national park. I'm merely using El Capitan as an example because of the shape of the mountain, and it's well known, so people can identify with its height. But, I bring this up because if the plane flies below the top of the mountain, but above the ground level, how high up is that plane? What is illegal when looking solely at the height of the flight?
I honestly think that there needs to be some considerations taken into account of location, with the way that the FAA classifies the 400 ft AGL. And maybe they do, but don't want to state that because some idiot will argue that there's a building half a mile away that's higher than 400 ft that a plane could fly into; I don't know on that. But, I can see where there's a lot of mess and argument coming, and being the way that the government has traditionally been, it may just become a blanket "no exceptions" type of thing.