Two days ago my wife and I climbed to the top of the main highest sand dune in Great Sand Dunes National Park, which took us a solid hour uphill. Near the top, I heard a giant mosquito noise, and saw a drone about thirty feet above. I was surprised as I had thought they were illegal in National Parks. Lo and behold, they are. The tech geek oriented readership here may not be aware, or appreciate, the traditions within Parks which mandates no use of power machines (only recently have exceptions even been made for helicopters during construction and maintenance, although rescue use is exempt). Normal upkeep is done pushing nonmotorized wheelbarrows, etc. The point is to maintain as much as possible the pristine ambiance both for humans and wildlife.
Park tradition is to allow recreational use by foot; no mountain bikes on trails, no dogs beyond parking areas and vehicles. Drone fans fail to acknowledge that others rights come first in many of these situations; your indulgence of a hobby, or photographic profession, infringes on the quality of experience for all who are hiking within a supposedly natural area. There are many other regulations and restrictions regarding firearms, glass containers, etc.
Perhaps you advocates will get your way soon anyway, as the wholesale deconstruction of a hundred years of preservation is rapidly moving ahead. Of course, then there will be little left of interest to photograph other than strip mines, drilling towers, and amusement rides. The end of our national experiment will be undone by rampant self-interest and selfish indulgences.