Phantom rings

So I'm talking to my neighbour and he says he has a story to tell me that I might find interesting. He said he had noticed that sometimes when his doorbell rang, he'd go to his front door only to find there was nobody there - but there was somebody at our door. Now, he has a wireless doorbell - so of course he assumed we had one too. Well, he was half right, we have a wireless doorbell extender, so that we can hear our wired doorbell downstairs in the basement. Whenever our extender transmitted, his receiver dinged.

What made me laugh is that we've been experiencing the exact opposite. Our extender receiver had been experiencing phantom rings when nobody was ringing our wired doorbell and we thought there was something wrong with our extender. Now that he's changed the wireless doorbell's code, everything seems to be fine.