More ranting and raving
So a Reaper or Predator will RTB if Comms are lost. How do they manage without their engines? -
Rigger - these two drones you refer to are highly sophisticated. There is on board software that handles altitude, direction, and airspeed. Ever in the much smaller Shadow RQ-7B these are totally managed on board, when in otonimous flight mode such as when the operators loose link. It's all up to the operator and how he loads the instructions to the on board auto pilot prior to launch. These peramiters can be updated and changed while the aerial vehicle is in flight.
DauphanDude lost comms to me means I can no longer get the aerial vehicle to respond to real time control inputs from the ground station. There are slight variations to what each vehicle will do. That's up to what you programmed into the vehicle prior to loosing the link. Some of the options are to place the aerial vehicle into a glide which means intentionally grounding it, no matter what obstacles are in it's path. Another is to program a return home feature. This allows for the aerial vehicle to fly a bee line straight back to a predetermined geographic point, remain at a specific altitude and circle until fuel is exhausted or a ground control station regains comms and issues further instructions. The danger in the return home is that there is NO SEE AND AVOID. If dear old mom and pop in a Cessna happen to cross paths while this drone is bee lining it home, the drone won't turn, it won't climb nor descend. This is why development of sense and avoid is paramount to these systems.
Gomerpylot - I do not know where you operate meaning what country or airspace. But if you are squawking and talking I know for a fact that any military operated drone operator WILL know you are near. As I said there are safety measures that the military goes above and beyond what is required. Namely tactical early warning radar. The radar is ground based and designed to pick up cruise missiles, Tactcal Helicopters, and fast movers flying NAP of the earth. Your Low flying helicopter, guessing that its much higher the tactical helicopters fly are easy peasy. Look it up its called the sentinal radar. This is all conducted in restricted airspace. Not saying that you were inside airspace that you were not support to be, but maybe just maybe what you seen was a wayward R/C aircraft. Also predictors and reapers operate above 18000ft. The shadow is typically at 3 to 6 thousand feet. Down in the weeds, below 1000ft you most likely find ravens, another UAV just the bird! Its mostly styrofoam, even held together with tape and designed to break apart upon landing. It's also required to be flown in restricted airspace.
I have said before that some drones fly in the NAS through a certificate of authorization (COA). Can't speak about the US Customs birds but the US Army is required to have either a chase aircraft (most of the time a OH-58) or ground observers with radio comms direct to the drone operator. Giving the distances involved, chase aircraft are mostly utilized. So even if you didn't see the drone, I would hope you at least seen the Kiowa, hot on the drones a$$.
Just my 2 cents here.