Thats what happened at the float fly. A guy that flys by himself turned on when I was up, luckilly, my plane didn't even know it. I watched 2 guys flying in a glider contest one time both on PCM, both on the same ch, standing 50 feet from each other. Then they realized it. Unfortunately, the one that paniced flew over the others head, that was a bad thing. He didn't have the failsafe set and the glider tucked and the wingtip caught a kid. Not a good situation. It is good if set right, but given the wrong flight attitude when it goes into failsafe, or someone not setting it, could lead to disasterous results, just like anything else. It can bite you at times.