By calling them when I arrive and watching them come out of it. I've fucking done this before. If you're buying something as serious as a car in a private transaction, you need to do more than look at it for two minutes before you hand some stranger cash and roll out. Anyone I've sold a vehicle to has come to my house and been there for at least an hour, anyone I've bought a vehicle from, I've gone to their house and been there at least an hour. For fuck's sake you people act like you do all your deals in public housing projects within a five minute window. Look up addresses in advance and don't deal with niggers, it's real simple.