Originally Posted by jiejie

As I said upthread, this phenomenon only occurs with online bookings made directly with the airline. If you purchased using a credit card in person at an airline office or travel agent, they'd verify the card on the spot and watch you sign the charge slip, and there would be no notation in your PNR for the check-in agent to request the card again. Ditto for using Expedia or other online third-party agent, as that 3rd party acts as a financial buffer to insulate the airline from fraud to a large extent.