It limits the speed they can travel and the radius of turns - but that's much more of an issue for something airborne than on the ground.
Agreed that not having to trail one is an advantage, but it sidesteps the wireless 'arms race', although as a datacomms guy I'm curious why spread spectrum isn't the answer.
Written by Bob Koure
Retired software architect, statistical analyst, hotel mgr, bike racer, distance swimmer. Photographer. Amateur historian. Avid reader. Home cook. Never-FBer