TweetHey Brother,
I just did this like a few days ago. I called my insurance company and asked if I was covered if I rented a car. They checked my coverage and I was completely covered. They even had discounts with all the major car rental places which was damn cool. Saved me close to $50 for a weeks rental with unlimited milage.
Also, if I choose to upgrade at the desk they will have the discount code in my file and and I can still save.