Just because a credit card charge dispute filed with the bank against a car rental company resolves in favor of the credit card customer doesn't mean that the car rental company (whether it be a franchise location or not) won't still claim the disputed amount is due even long after the bank has made a final decision on the matter of the charge. It's anyone's guess to what extent they will go in pursuing a domestic or international collections effort on a car rental after a card charge dispute has been resolved, but sometimes they do try; and at other times, you find out only at your next attempt at a rental.

I've had more problems with Sixt than any other major car rental company. On one of my last rentals with them in the US, Sixt tried to charge me for damage -- rooftop scratches -- scratches that I had photographed, video recorded, noted down and communicated to two Sixt reps prior to even getting in the car. Even after the bank sided with me about the charge dispute over the damage charge Sixt had flagged down my driving license or something to frustrate a future rental. We ended up having to go back to dealing with the Sixt car rental facility that "owned" the car to finally get the matter resolved and get that block lifted. So glad I hadn't prepaid the Sixt rental that time.

Sixt delivers from a better fleet on average in the US and Europe than what I get from Hertz, Avis, or Europcar. But Sixt's approach to customers when things go wrong (and even with up-selling) leaves enough to be desired that Sixt gets me only when Hertz, Avis and Europcar don't fit the bill as well for me.

For anyone with a Sixt rental charge dispute -- even after a charge card dispute has been resolved -- avoiding prepaid Sixt car rentals makes sense. At least until after doing a few post-paid/pay-at-pick-up Sixt car rentals.