I'm not saying that Amex is not being charged, rather that it happens all at once with all the recorded data and not on the spot at admission to the club. From what I've seen in the CRCs, the attendant looks at the card to verify its Plat/Cent, then they simply swipe and let you go on your way. Never do thy look at the screen for an approval or anything, nor do I believe that their system is set up to do a test charge to verify card validity.

My understanding of how the system works is that the numbers are all recorded and Amex is billed for those visits in a batch, whether it be end of day, end of week, month, quarter, etc... Amex might be verifying card #s when they are submitted in that batch, and I'm sure an inactive card will come up in their system as being used inappropriately, but it will be after the visit has taken place. If the same inactive card is used repeatedly, Amex might take further action such as contacting the (former) cardholder or sending out a blacklist if it's used at the same club. I don't know if Amex will care to do anything for the occasional visit, but they might refuse to pay and the respective airline/club will end up eating the cost.

I'm not advocating that anybody do this; it depends on an individual's personal morals and ethical code. A risk that one entails by doing this is that Amex might decide to reactivate their platinum account or charge the platinum annual fee if the former cardholder is still presenting the card for benefits. Amex might look at it as "well brosnan6 is still using his old card for platinum benefits even though he downgraded to [insert card type here], so we are allowed to charge him the platinum annual fee instead of whatever he's currently paying." I am not a lawyer so I don't know if this is allowed on Amexes part, but it certainly seems like something that could happen