This is kind of fun, so to play some more: suppose the spoofing platform is mobile; say, a UAV that starts out very very near the target of the spoofing, and gr

This is kind of fun, so to play some more: suppose the spoofing platform is mobile; say, a UAV that starts out very very near the target of the spoofing, and gradually moves away at a rate designed to confuse such a check. You can see why military stuff gets expensive. The world gets complicated when folks are actively trying to screw with you.