A quick question with a complicated response. The rental car companies have made this relatively complicated. Many coverages exist, however, there are a few caveats. Coverage may transfer but has a few gaps. From my experience, many insurance companies attempt to have some of the items listed below waived as part of your claim defense should an incident occur and the claim is covered by your insurer.
Since you have full coverage on at least one of your autos, the deductibles of $100 Comprehensive / $500 Collision, as well as the Bodily Injury LIABILITY policy limits, automatically transfer to a temporary, rented, private passenger auto less than 14,000 GVWR, (such as minivan’s or SUV’s). The auto must be operated in the contiguous US, its territories, Puerto Rico, and Canada. Liability coverage is extended up to 21 days, but physical damage (comprehensive and collision) is EXCLUDED for such larger vehicles as with many U-hauls, some 16 passenger church vans, and autos with GVWR greater than 14,000 pounds, as of January 2016.
In addition, you may be financially responsible for diminished value should you severely damage a rental car. The rental car company may bill you directly for this since they replace their autos every year or so many miles to limit breakdowns or interruptions in service.
In many cases, the rental car company has contractually bound you to accept additional liability, by contractually requiring you to be responsible for the loss of use revenue (i.e the lost rental time while repairs take place to their damaged auto, and are unable to rent it)… Typically, NC personal auto insurance does not protect against the aforementioned items. Should the rental car company request such reimbursement for loss of use or diminished value, the insurance company may challenge this allegation, in an attempt to get it dismissed depending on the circumstances. This is where the rental car company attempts to fill in the gaps they created, by selling the damage waiver to include the above omissions they created contractually. A bit sneaky some may say!
The damage waiver, for a daily rate, may exempt you from the burden of physical damages, and liability contained in their rental contracts while utilizing a rental car, instead of financially impacting your respective primary auto insurance. Essentially, it may be a relatively hassle-free way to rent an auto as you travel greater distances away from home, in busy cities requiring street parking, or outside of the US. Arguably, this is where the bulk of profits result for rental companies by self-insuring. Is it worth the additional charge to you for complete protection?
Hope this helps you decide if the rental car company’s additional damage waiver is worth the price, given that it often adds a relatively large amount to the overall cost of the rental charges.