If one of those things, for whatever reason, blacks-out and kills someone they will be permanently banned.

A way around this would be to permit them to fly above specific areas, via predetermined, controlled routes, that pedestrians should avoid to minimize the risk of accidents.

But the technology for the police (or any authority) to ID those vehicles and control what they are transporting (or state of transporting) it's already here, someone needs to put the pieces together and it's ready to go.