I've heard of a salesman selling someone's trade in before it was actually traded in. The worst I saw was a promotion company's guy selling a 2002 Z28 Camaro to an 80 year old man ($8k gross profit) and then the old man coming in the next day and trading in the Camaro on a Toyota Solara ($6k gross profit). Sales guy made $3500 on the oblivious old man in less than 24 hours.