Does anyone have more information on this promotion? The letter I got said $25 discount for joining AC on the day you visit using the 1-day pass, and another $50 if you use an AMEX card. I got the $25, but at the AC they didn't seem to know anything about the AMEX part, and I gave them the whole letter, so I don't have anything to show for it. Is it possible this will just appear on my AMEX statement as a credit or something? Since I don't have anything to show them to try to get them to do it at the AC, I may be out of luck.