even amateur balloonists are supposed to contact ATC so that NOTAMs can be issued. i launched one to about 90,000'. ATC asked me if we had any kind of radio beacons for them to follow, but we were way too small for that. we did have a GPS that we could get some altitude updates on, and ATC asked we update them at every 10,000' for as long as it could be tracked.

if someone is operating a balloon and NOT contacting ATC, they deserve to have there thing shot down. that's just highly irresponsible. it's a simple phone call, and then there's no confusion on if your balloon is a foreign spy platform or not