What I'd like to know is what constitutes a "coupon"?

Presumably a physical paper coupon that you hand over to an agent is a coupon. Likely that coupon codes you enter onlineare too.

But what about membership IDs or rate codes you quote upon renting? Those effectively function the same as coupons too.

Anyway, this is maddening and very much reduces the value of the insurance in my mind. If I have to pay full price on the rental to get "free" rental car insurance, then it totally defeats the purpose of the latter. Or is that the point?