Originally Posted by Hydro Junkie

How about this, have all quads equipped by the factory with a low power transponder. If it's close enough to the airport for the radar to pick it up, it's close enough for them to get police out to it where it lands. If it's being flown too high over a known flying field, the ATC would know that as well and could call or send someone out to let the people know there is a problem. This could also be retrofitted to all receivers at time of manufacture that are used in all RC aircraft over a period of time.