When I saw your response, my first thought was that property owners (in this case, the county) might control the ground, but the feds control the airspace. And this might mean that a county ordinance against you playing Frisbee golf in the picnic area might be banned, or launching aircraft might be banned, etc.
This morning I was watching this video which basically said the same thing I was thinking.
Jump to 8:50
The 2 things about drones that would legitimately piss people off are safety and privacy.
Flying over people is regulated by the FAA, and then there's the general peeping tom crimes regulated by state laws, like pointing a camera in somebody's window or over their privacy fence.
FAA interview on operations over people:
