A friend's post on FB made me recall a similar situation.
In his case, his IR-linked headphones now play a local AM station at very low volume whenever he's near an electrical outlet or switch in his house. Yes, it really happens, other people hear it too.
In my case, I recall a similar situation but I can't recall what the "receiver" was - it was in the 80s so if it was headphones it must have been wired but I don't recall having a walkman or similar at that time.
In any event, I can't seem to Google anything useful on this, although I'm sure I found an explanation in the 80s. IIRC, it was basically a crystal radio. It has to do with the contact between the wiring and the electrical boxes forming a cupric oxide diode, the wiring acting as an antenna, but I don't recall how you get the LC part. And then how would the headphones pick it up?
Does anyone have an actual explanation for this?
UPDATE: I woke up this morning and recalled the receiver in my case - the telephone. You could hear the local station very faintly in the background, but not over the sound of the dial tone.