Critter-hunter, I loved your story about your experiences in the RC controlled planes hobby. How "telling", eh? And your analogy is right: the same psychology happens in metal detecting too: There might be a place where no one has ever had a problem detecting before. But lo & behold, someone thinks "wouldn't it be nice to get the ok in writing, so that we don't risk arbitrary capricious questioning by a cop or gardener in the future?". Or "let's go ask at city hall, to make sure it's ok to do", or whatever. And just like in your story, someone in authority tells them "no you can't" or hands out silly rules that ....... previously ...... weren't even there. It's the old psychology of "no one cared, till you asked" routine.
And control-freq, to answer your question about how a "license" or "permit" would still be good, to deflect busy-bodies or bootings, here's my answer to that: You/we should NEVER go looking for "permits" or "licenses" to PRE-EMPT such a thing (lest you merely get the scrutiny brought to your "pressing question", as stated in the first paragraph). Instead, any such petitions, permission-seeking, permit ideas, license ideas, etc.... should only be to combat some rule already in place. NOT as a pre-emptive measure (lest you merely get a "no", where no one ever cared before).