ORIGINAL: J_R
What works for one group may or may not be safe for another. As an example, sailplanes have different needs in clubs devoted to sailplanes than 42% gas planes would at a club for powered flight. You would probably not need 400' at a park flying site. It is up to the individual or club to come up with rules that make sense, and keep the site safe.
That is why I say with the advance in all types of flying the AMA could really address this issue as a whole. There has become a real mix of flying. I am not sure they know what to do about it.