Schneier has a good article on the Psychology of Being Scammed. I come from the report “The psychology of scams: Provoking and committing errors of judgment” was prepared for the UK Office of Fair Trading by the University of Exeter School of Psychology. Schneier does a good analysis and points out some interesting aspects that it appears that victims tend to over analyze the scam and then hide their participation in the scam.
…it was striking how some scam victims kept their decision to respond private and avoided speaking about it with family members or friends. It was almost as if with some part of their minds, they knew that what they were doing was unwise, and they feared the confirmation of that that another person would have offered. Indeed to some extent they hide their response to the scam from their more rational selves.
…scam victims report that they put more cognitive effort into analysing scam content than non-victims. This contradicts the intuitive suggestion that people fall victim to scams because they invest too little cognitive energy in investigating their content, and thus overlook potential information that might betray the scam. This may, however, reflect the victim being ‘drawn in’ to the scam whilst non-victims include many people who discard scams without giving them a second glance.
This points to the fact that they intuitively know that something is wrong but disregard the prompting to stay away. This goes back to my theory that you need to trust your instincts. If you feel it isn’t a good deal or is even dangerous, stay away.