I had an NX Coupe that a customer gave to me for 10 years. I had it sitting around for a couple of months, then decided to do something with it, and fitted another engine. I told the guy we needed to change to ownership, and that's when he told me there was a debt on the car -$4,000! It wasn't even worth $1,000, so I drove it for 5 years under his name, then finally changed it into my name. Always prepared for it to be towed away, but it just wasn't worth recovering.
My BIL left me an old Corolla when he went overseas...and someone stole it. We knew who he was, but he had witness protection, so couldn't do anything about it. When the BIL came back a year or so later, I gave him my Corolla as a replacement. When he was finished with it, he left it parked down the road with the keys in it...it took a few days to disappear.