With regards to the main power contactor, you could run the power for the contactors coil through a small 6V relay powered by the receiver power supply, then through the microswitch which the servo activates. Arrange for the 6V relay to be downstream of the receiver to minimise the chances of a cut wire leaving the relay powered while the receiver is not.

Regarding servo power - I wouldnt recommend any way of getting around tech checks, it was more to point out a possible flaw in the rule. There are also legitimate reasons for running your servos on a different power supply to the receiver.