Having had an accident in rural Italy, I strongly suggest that you just pay the price of CDW with no deductible. The vehicle was rented from Europcar with a voucher issued by AutoEurope paid for with a Diner's card.
Other than 2 hours of paperwork hassle with the Polizia Stradiale, there was no problem returning the car to FCO. Europcar was so blaise' about the whole thing that I probably could just have handed them the keys and walked away. They actually had to find a piece of paper so that I could give them a brief statement of what occured.
As I understand it, full coverage is mandatory in Italy. Credit card insurance just does not seem to work.