"He who marches out of step hears another drum." ~ Ken Kesey
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