I would be careful about getting into peoples' cars, although I guess this was at a pretty public place.
I always try to meet at Starbucks for CL stuff (I think that is the official 'storefront' of CL now), every couple of months I read a horror story about some guy getting robbed or even shot by CL thieves, pretty scary stuff.
I have gone to peoples' houses, but then there's a clear email trail and location, I don't think a thief would have people come over to their house and then rob them. Worse comes to worse let them steal your money, then leave and call the cops.
One time I sold a notebook computer to some guy who asked to meet me outside his apartment, because he didn't want his girlfriend to know how much he was spending on it. In retrospect, that's not a great sign- he could've given me a random address not tied to him, and maybe used a stolen cell phone or something like that. But he was totally legit and I did complete the sale.