I guess it’s possible for the TC to be stolen, but really unlikely. Besides paying attention to whether you think the person is honest or not, I’d create a bill of sale to take with you with a space for VIN and his full address and phone number and have him/her sign. Validate his name/address with his/her driver’s license.
If it doesn’t have a VIN, then I wouldn’t buy it. I’m assuming that it would have to be fairly new if it is worth more than 10K. I don’t think there are probably any newer TCs that wouldn’t have a VIN.
