My towbar connects with a ball hitch. Sometimes I use a lock and sometimes I don't. Either way though, I don't think a single pad lock would slow me down much. It is something I have thought about though. While both vehicles are insured, I would not want to go through the hassle. Also who wants to be in the middle of now where with no drivable vehicle. At least if you can save one, you are not stranded. You always want to minimize the damage. In the OP's case, while I don't know if he did, he could have easily continued his vacation.