The idea sounds great but has anyone actually done it and proved it works?
It does work, I know someone who regularly does this with their Ute. I cannot recall any instances of aircraft but would be very surprised if it's never been used judging by then number of farm paddocks that get used by aircraft.
Just make sure the fuel tank is full with no air in it.
Why? If there's any spark it will be at the point of contact not in the fuel tank. Unless the aircraft is leaking fuel there won't be sufficient vapours to cause ignition.
Poorly designed or badly maintained electric fences can create sufficient electromagnetic interference to cause problems for nearby telephone, radio, and television reception.
Correct, this happens where part of the fence is shorting to earth, i.e. the fence wire is in contact with the metal standard or the fence wire is touching the ground or green organic matter that will conduct electricity, causing a spark to occur.
Unless the aircraft is parked over long grass, no part of the aircraft structure is going to contact the ground, except for the tyres which are insulators anyway.
The electromagnetic interference does not affect the receiver directly, it interferes with the signal being received by the receiver.