Wirelessly posted (BlackBerry: BlackBerry8530/5.0.0.601 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)

"Really, I don't want to double cover, but I also don't want to go too far the other way. for 12 days, it seems AMEX's $25 premium coverage is the safe way to go, no? Peace of mind has a value, in my book."

Don't throw your money away. What would you get with the $25 coverage that you wouldn't get with the free coverage? As long as you are not using a free-day or dollars-off coupon on the rental, a card that provides free LDW coverage -- even if it is "secondary" coverage -- will cover your rental. "Secondary" coverage becomes primary when the renter has no other collectable insurance. Or you can charge the entire rental to your Chase/UA Explorer card, which provides primary coverage even for renters who have other insurance (without charging you an extra $25 per rental).