I don't know. One could easily imagine AC blocking the passenger from purchasing tickets, blocking use of the credit card, or blocking use of the credit card via the website. Apparently the first isn't happening as no one has been apparently put onto some sort of "no fly AC" list by AC. AC might be less suspicious if the credit card is used in person as that means that the person has the card itself and not just some stolen credit card number or a badly made clone.