I bet there'd be a damn good market for a cheap failsafe with built in self charging battery. Turn the RX on and it automatically charges it's tiny battery. It senses that the receiver just shut down and it expels it's tiny battery power setting the throttle servo to neutral. In fact, with the amount of power necessary, I bet a single, fairly small capacitor would do the job just fine. Could be used in boats, planes, and offroad + onroad cars.