看看这个。
“All four major networks require cardholders to charge their entire rental car purchase on their credit card and decline supplemental insurance/Collision Damage Waivers offered by their rental company in order to be eligible for coverage.
随便google来的。免得说是常识, 又被说太绝对。
http://www.cardhub.com/edu/rental-car-insurance-credit-card-study/