As I indicated on another thread, the requirement to show the credit card is pointless and stupid in the first place. They get to see your picture ID anyway, so there is already no question about your identity. The credit card company has already authorized the charge, since in United's res. system the ticket has already been "issued". Therefore, the only thing accomplished by this charade is to annoy passengers, reduce the convenience of using E-tickets, and give officious and self-important gate agents something to do.

It's time for United to pay attention and stop this nonsense NOW.