RC airplanes don't fly in and around crowds as the moron from Germany was doing.
Lots of you tubes made by camera drones at events where thousands of people are gathered.
Watched one from a mud truck race where the drone was hovering over people and came within arms length of kids playing in mud. Later the drone did crash into a pickup full of adult mud bogging watchers after the drone came was brought down by a rooster tail of mud.
IMO the guy that used the drove in Yellowstone new the rules but like many folks simply thumb their nose at the rules/laws. He got off too easy.