Hello Wayne:

To be honest, I have not reseached the answer about control - however APRS
is used frequently in vehicles and animals that are not occupied by
amateurs. They are installed in balloons, used on search dogs. I am a ham
(K7FM) and have had an APRS unit installed in my car. It shuts down when
the ignition is turned off and I have the software quit sending out reports
if there is no change in position. I am sure I could write software that
would cause the transmitter to quit transmitting a position report when the
power was turned off.

So, the answer is I do not know the fine line about control, and the main
point of the post was to let soaring pilots (many who are hams or know hams)
of available technology. If it useful, they might just want to get a ham
ticket. My wife has no interest in radio at all but studied the question
pool over a weekend and became N7WXY.

Colin Lamb