What Dave said.
If its on 27MHz, the receiver will take any signal as an instruction, and the first thing to be instructed is usually the rudder. Unless you have a good reason to flatten the battery, don't leave the receiver switched on if its transmitter is not on.
I doubt that the scooter would use a radio to control itself, but who knows? - it might be cheaper than a wiring loom. It does seem that switching on gives a burst of interference, which is a bit naughty. Hopefully it won't work the other way round.