This is coverage for any occupants in the case of injury, death, or damage to personal items from an uninsured or under-insured motorist. If you live in the United States and have auto insurance, it's not worth your time to even worry about this. But if you are visiting from another country, seriously consider this, as insurance coverage in different countries may differ widely.
All of these insurance options are just that: OPTIONAL. You are not required to purchase any of them, and most credit card-carrying American motorists are already covered for everything these added plans offer.
If you do decide to add insurance, here's some advice from one of our experts: "Never ever, ever, ever, ever, ever, ever, ever, ever prepay insurance through a third-party site. Most of those policies are complete trash and will serve as nothing other than peace of mind -- until something happens. Whomever you rent with will still charge you, directly, for any and all of the damages and YOU will have to track down somebody at Priceline or Joe's Car Insurance or whoever to get things covered. And frankly, no one ever reads the terms and conditions and they are masters at hiding stuff in fine print that makes their contract virtually worthless." So, there you go.