Credit Card Registration - Millennium - Hong Kong

When / where do you register the credit card for the onboard account?

At Checkin (although X-Pass only has lat 4 digits of credit card No., or once onboard at GS)

Thanks

Normally at check in if you have indicated on your Xpress pass that you will be settling your account with a credit card.

Lately, though, I have been putting" cash account in the Xpress pass and then going to Guest Relations a few days into the cruise and giving them the credit card info. That came about after there was some trouble in the Miami terminal with some cards being compromised by a shoreside terminal employee.