We had an interesting experience once involving CDW, and as a result, we always pay for it whenever we rent a car. Specifically, we rented a car in Fort Myers at the airport in the evening. It was dark, and we didn't notice any problems at the time we rented. The next morning, when the car was parked at the hotel, I noticed that the one bumper skirt was asymetrical compared to the other. There was no paint, just a little shallow dent in the Foolishly, we did nothing about it. Then, about six weeks or so later, we got a letter from the rental agency asking about the "accident" we had.
We learned several lessons. One is that we carefully inspect any rental car and report any little ding in the paint at the time we pick the car off. We are picky to the point of being a major PITA. I surely don't want to be the one to pay for a $3000 paint job for something I didn't do. Secondly, my brother, who is an attorney, told me that there may actually have be a subsequent accident involving the car, and that we should just report that we didn't know of any accident or even make any mention of the dent that I had noticed. Finally, he told us that the rental agency would likely not have bothered to contact us at all if we had purchased the CDW. So, we always do. It is worth the peace of mind to us.