With regards to the 2nd theory: Even if the 22KHz switches work backwards there may be a conflict with the 2 receivers fighting for control of the 22KHz switch? If both receivers are on say C-Band, 1 will be 22K ON and the other receiver will be 22K OFF and only one of the receivers will/may control the 22KHz tone to the switch and the other may not pass signal? This is why I listed this theory 2nd.