Not necessarily a craigslist warning, but one just in general. I know a year or two ago there was a rash of similar stolen vehicles. Guy would meet someone to test drive the car and would never come back and the car he showed up in ended up being stolen. Supposedly had been going on for a week or two, ever few days he would change out cars. It's honestly a danger regardless of how you go about it, you could even ride along with the guy and he pull a gun out on you and tell you to get out down the road.