Originally Posted by fti

Based on personal experience, AmEx will not cover you if you have any sort of 'free day' coupon. I rented a while back while overseas and used a free day coupon. Since I 'did not pay for the entire rental using AmEx' they refused to cover the damage claim. Of course I paid for as much of the rental that was out-of-pocket but they claimed using a free day coupon invalidated the collision damage waiver. Not sure if that is also true if one were to use $ off coupons, which are more common.

In the end my claim was reversed by a different division of AmEx as frivolous ($450 for a 1/2" scratch on the wheelwell that was probably there when I initiated the rental) but that is besides the point.

I now use Diners Club for my rentals - primary coverage anywhere in the world and costs under $100/year. Also gains me access to some airline clubs overseas.

Just know what is and is not covered before you venture out renting cars making basic assumptions that could be wrong.