It could be that, Chris, or it could be someone up and bored. When I was active and couldn't sleep I'd throw on all sorts of stuff, from old shows to university lectures and garage sale answering machine tapes on in the middle of the night to see where it went and make people go "WTH?". If one guy has done it, I'm sure others have, too.
Where was SDR when it was needed to record those classic bits of radio history?