Also, it appears that the primary cardholder can only bring in family members as guests, while American Express Centurion and Platinum allow the cardholder to bring in any two people:
It will be interesting to see how AA verifies immediate family status and if AA renews their arrangement with American Express.
Not entirely correct. This from their website:
With an Admirals ClubŪ membership, you and your immediate family (or up to two traveling guests) have access to over 40 Admirals ClubŪ worldwide locations.
Bold statement by me to emphasize any other two guests.