I called my credit card company. Their policy is really solid. Their coverage is primary, and they cover up to the vehicle's original MSRP, as well as NOC and any and all deductibles. Makes you wonder what's in it for credit card companies to offer something like this in the first place.

Anyways, they told me they hadn't heard of or advised any customer to do anything like buy the rental car coverage but write "I decline CDW" or "I decline my vehicle's collision and damage coverage" or anything like that. So I appreciate all your advice, but I don't think I'll do that. I'm leaning towards just declining rental car's CDW. Let me know if anyone has any additional input on this.