Well, I signed up my wife for the premium protection plan and we charged two Hertz rentals in Germany to her Amex card. Both rentals were made with points and the taxes & fees were charged to Amex. No additional charges for the protection plan showed up on her statement. I assume we never were covered, but luckily nothing happened to the cars.

I verified online that her cards are enrolled, and when we returned from our trip there was a confirmation/info packet from the protection plan in the mail. Not really sure what happened here, but I am going to cancel the plan.