In the last month up to sixteen drones have been spotted at night fly together. Commercial enterprises who use drones in the area deny any involvement with them. They fly in the restricted space designated for drone and do not require notification of the FAA. It has been reported that they are quite large (up to six feet?) although that might be in error. The particularly disturbing part is their origin has has not been determined and their low flight paths may be hard to track, I guess you could conjure up all manner of possibilities but it is hard to come up with a reasonable or legitimate purpose for doing this without notifying the public. One drone at night would be irritating but sixteen?