It also serves as a test to make sure no one is flying on my channel.
I turn on the receiver only. If the device does not go into lost plane mode,
then someone else is on my frequency.
I don't think it's a good idea to turn on the receiver (the plane) without transmitter unless you have PCM anf failsafe programmed in it. It's just becuse, if nobody is flying your frequency, your servos will go crazy and they can eazy break gears, your surfaces or just burn the electronics (digital servos).
The rule of thumb is: Transmitter first, receiver second.
RysiuM