Originally Posted by
leonard016
The other way is to give AA some access to verify? I don't know when they swipe the card (such as Amex Plat) do they send electronic records to the issuers (Amex, Citi, etc.) or are they actually able to verify information provided by the issuers? Any thoughts?
It's possible there is data already encoded in the magnetic strip of each card indicating whether the card is the primary one on the account or an AU card, which the Admirals Club software could have been programmed to read.