I did book one time a plane ticket (LHR-ORD-LHR) + car on BA. Getting the car significantly lowered the price of the plane ticket as it was a 4 nights trip that did not include a Saturday night. Car was provided by Avis. Since I paid everything with Amex I did not feel I needed to take extra insurance. The only issue is that they gave me a SUV when I had booked a car. It was an upgrade and would be seen as such by most people but I'm not used to them so would have preferred the car I had reserved. If I remember correctly they tried to convince me to pay more to upgrade to a SUV but the reality is that they did not have a car on their lot so they ended up having to give me the SUV. Discussion about this issue took an extra 10 minutes which was not pleasant as I would not budge and pay more. The one thing you have to make sure is to check the outside of the car before you leave the Avis lot for dents and scratches and report them to the Avis employees. Even take pictures with your cell phone.