‘Running a scam’ means the tactics that are used to take advantage of the ‘mark’. Within one (or more typically, two) dates, the predator will begin to groom the victim by ‘sharing’ some information that makes him seem very vulnerable. Information like how hurt he was in his last relationship, or how the ex will not let him see the kids, or the death of a close friend, etc, etc. This tactic is to increase your confidence in the predator, and it also places subtle pressure on the victim to ‘share’ equally in turn, giving the predator yet more information to shape his presentation.
Many personality disorders, though, have a very difficult time containing their ‘crazy’, and will make small errors when something out of place ‘leaks out’. This will typically be mentioning something that is oddly inappropriate for the stage of relationship that has begun, like: ‘how do you feel about sex toys?’ If the victim is startled or disquieted by the comment, the predator is very quick to pour on extra charm, sweeping the comment out of existence. Only later (usually much later) does the victim recall these weird comments and realize that they ‘missed’ something important back when the new relationship was all hearts and flowers.