A tactic I've used in the past is buying a burner number (prepaid sim), called recruiters with a fake name, number and resume and asked them to provide details about the job which many of them name completely. The ones that don't generally indicate that other recruiters do exactly what I'm doing to them in order to steal clients.
I don't feel bad about screwing over an industry which has no place in the modern world, particularly when they're opportunistically trying to make a buck from me and/or my future company while adding very, very little value :)