Uh, it used to be that way, but that changed with new regulations when drones became an issue, now on the front page of the FAA is -
"FAA rules apply to the entire National Airspace System -- there is no such thing as "unregulated" airspace. Drone operators should be familiar with the difference between controlled and uncontrolled airspace, and where you can legally fly. Controlled airspace is found around some airports and at certain altitudes where air traffic controllers are actively communicating with, directing, and separating all air traffic. Other airspace is considered uncontrolled in the sense that air traffic controllers are not directing air traffic within its limits."
No person may operate a small unmanned aircraft over a human being unless?
(a) That human being is directly participating in the operation of the small unmanned aircraft;
(b) That human being is located under a covered structure or inside a stationary vehicle that can provide reasonable protection from a falling small unmanned aircraft; or
(c) The operation meets the requirements of at least one of the operational categories specified in subpart D of this part.
[Part D] - To conduct Category 1 operations?
(a) A remote pilot in command must use a small unmanned aircraft that?
(1) Weighs 0.55 pounds or less on takeoff and throughout the duration of each operation under Category 1, including everything that is on board or otherwise attached to the aircraft; and
(2) Does not contain any exposed rotating parts that would lacerate human skin upon impact with a human being.
(b) No remote pilot in command may operate a small unmanned aircraft in sustained flight over open-air assemblies of human beings unless the operation meets the requirements of either ? 89.110 or ? 89.115(a) of this chapter."
There is of course much more regulation in regard to it than that, that is just the frame work which legal drone pilots start from.
I had a thread about this a few years ago when they implemented rules for drone flying, basically they cannot exceed 400' without ATC notification and permission, if you look at prohibited places maps, drone flights are forbidden for miles around airports (varies with airspace classification), over towns, roads etc, without a commercial drone license. Even then are required to have transponders so the ATC radar can detect them and have to file flight plans. For sport drone pilots, they have to have a spotter who has eyes on the drone entire time with the pilot, so it has to stay in visual range.
They really wanted to make it outright illegal to fly FPV beyond visual range, but just made it so tightly regulated its designed to highly discourage it, which some people ignore anyway.
The short version is essentially for this to happen legally, they know who is doing it and why, and if not the feds sure seem awfully nonchalant about it.