we get the occasional trade in where the owner is happy to chat with or provide all the previous information on the car. usually we let him know that would be great! thanks, we'll mark it ono the file!...
but its not worth the issues that could arise in many cases, so it rarely actually happens.
two days ago i got a phone call about a car on our lot from the previous owner... he wanted to let me know that it was listed as having a trailer hitch when it actually didn't.... not sure why he was tracking the car so much, but people feel pretty connected to their cars.
oh, and for the carproofs, i keep a copy in the file and if someone wants it, i will copy it for them. it seems to be fine even though its not an actual download from that day or anything. falsifying a carproof is actually something that is considered fraud and you can get in some serious trouble, so i think for the most part, you're safe there.