Very likely your personal auto insurance provides no coverage outside of North America, and the issue will not arise. In that circumstance the free "secondary" coverage provided by most cards comes into play because you have no collectable insurance. However, bear in mind that credit card policies only cover damage to the rental car. If you damage another car, other property, or there are injuries, you may be responsible and you need to understand how you are protected by your own insurance or the insurance provided by the owner of the car.