Opportunity is missed by most people because it is dressed in overalls and looks like work. - Thomas Edison
Just for shits and giggles see if you can get them to send you a picture of themselves for your records or verification. Whatever terminology you want to use. Have them hold a sign with some stupid saying on it. I have seen this done before, it is very funny.
Lots of good ones here:http://www.419eater.com/html/hall_of_shame.htm