We had a situation two weeks ago where a buddy cord was pulled out of one of the transmitters while a student & pilot was flying.

This shorted the TX and caused it to stop transmitting! The plane went into failsafe with a slight nose down attitude at the time.

Fortunately instructor had the presence of mind to turn off his transmitter and turn it on again a few feet before the brand new giant club trainer went into the trees.

Wireless buddy boxes are the way to go.