we had a few things like that happen. every time it was at lease partially our employees fault, so we stepped up to get it fixed. one gal, we wrote off her journey.... we matched her payment to the penny, same term, etc. and got her a nicer/newer journey. other times, we fixed the cars, gave them loaners during the fix, or offered them a trade in of their unit at what it was worth in perfect condition and gave them a deal on some other vehicle on the lot.
just saying not our problem is really not something i have ever had to deal with. i suppose if it was totally not the dealers fault, it would be up to the customers insurance to chase the party at fault ('s insurance). not certain as to why when someone not affiliated with the dealer does something wrong, the dealer would be expected to foot the bill.
while the customer service might be lacking, not really a "stealership" worth comment.