Scott, the Operating Limitations for an experimental aircraft are the prevailing rule. Operating Limitations are determined by the DAR that does the certification and issues all the docs. A more common phrase in Operating Limitations is...
6. This aircraft is prohibited from operating in congested airways or over densely populated areas unless directed by air traffic control, or unless sufficient altitude is maintained to effect a safe emergency landing in the event of a power unit failure, without hazard to persons or property on the ground.
In practical application isn't any parking lot suitable for an emergency landing? Also in the real world there are nearly 30,000 experimental aircraft now in the fleet and they fly everywhere from the busiest airspace on down. I've personally flown my homebuilt RVs through various sections of L.A. airspace with no problem.