I have heard stories of stations making claims like that, then the carts jammed on-air!
A small AM station here in NJ, 1590 WERA, claimed for years to be transmitting in AM Stereo, when they never actually did. When I finally got a C-Quam receiver in 1995 I discovered they were mono, but thought that maybe they were using the Kahn system, which they had to stop using when the FCC made C-Quam the standard. But later a former engineer for the station spilled the beans that WERA never transmitted in AM Stereo of any kind -- the DJs just made it up.