That's a definite possibility. But he apparently got it to transmit on the output frequency, so it's likely he was also listening on that frequency. It would take me a while to get it to transmit on the output. However, if the radio has one button to do a reverse split, then it's possible he hit that button, in which case he wouldn't be able to hear the other guy. But my money is on the receiver desensing, especially if he says that it's a Baofeng or something similar.