It's been rumored that the military has been using implanted transponders for years in special personnel (nuke sub crewmen, Spec Ops, etc.). Maybe chemical warfare types, too? Maybe there's some truth to the rumors? Okay y'all...feel free to make tin foil references.
Scouts OUt! Cavalry Ho!
The Digital Angel is now being sold to civilians to to monitor dogs, children and HMO patients. Of course, why would the military ever use it?