There have already been deaths as a result of accidents with unmanned aircraft systems.
http://blogs.wsj.com/metropolis/2013/09/05/remote-control-helicopter-kills-man-in-brooklyn/ These systems have been in use by hobbyists for decades and have been called radio controlled model planes until the practice of blowing up terrorists with armed versions popularized the term drone. Technically neither the radio controlled hobbyists weapon, not the usual terrorist killer are drones, since they are under the remote control of a human pilot. A drone is an autonomously navigating aircraft that does not need a pilot at all.
Current regulations require that a pilot be at least 13 yo and require registration of the aircraft if it is over 0.55 pounds in weight and restrict it to an altitude of 400 feet. Drones weighing more than 55 pounds require special registrations. There is no requirement that the pilot have any training or competence and no license required to fly. If you are hit by a 54 pound drone falling from 399 feet operated by a 13 year old, that should make you feel much better. At least the responsible party will be identifiable by the official FAA registration on the wreckage.
When automobiles were first released to the public, there was also no requirement that they be registered or the drivers certified either. When there got to be enough of them causing accidents, however, regulations seemed prudent.