If the surname of the passenger travelling is same of the person who books, then they won't ask for CC in airport. I just recently got this clear when I booked a ticket for my sister. Though this isn't mentioned anywhere in the EK guidelines, the phone officer said that it is in their guide book . She then explained that when booking you can see that you will be able to change the first name of the Credit card holder but not the surname, which was true ^.