The problem with drone technology is that it is advancing at such a rate that makes it nearly impossible to keep inexpensive UAV devices out of the hands of nefarious actors. Drones have become so readily available at such low prices that anyone, almost anywhere, can buy drones, even if they intend to use the drone for illegal purposes.
Drones have become a serious public safety threat for many governments and organizations, including:
Airports
Prisons
Stadiums
Governments/Militaries
Critical Infrastructure
Data Centers
And many more