>it could easily start confirming their suspicions
to be fair it will easily confirm any suspicion for the reasons you laid out, so even if you have no technical knowledge just a bit of interrogation will break the parlor trick.
I honestly think this has little to do with the tech itself but that these are the same people who think the phone sex worker or the OF creator loves them or that the Twitch streamer they like is their best friend. 'Parasocial' is a bit of an overused word but here it literally applies, this is a kind of self delusion in which the person has to cooperate. Mind you this even happened with ELIZA back in the day too.