Most Credit Cards specifically exclude JA from their rental car CDW waiver (along with Ireland and Israel).
I know one that does cover the CDW is a World MasterCard. Cuts the rental cost about in half by saving the $30/day CDW.
But that is to cover their car if damaged or stolen.
Don't forget about Liability. From what I have read, Island includes that in their rental fee - don't know about other agencies.