not sure if this is the best place to ask, and nothing turned up in a search of the amex member rewards forum, but does anyone have a direct link to the full terms of the amex premium rental car insurance program?

the summary says it covers additional drivers, but nothing on the amex website explains whether it covers when i use the card to pay for someone else's rental. amex doesn't charge the fee until the rental is actually picked up, and i want to find out in advance.