http://consumerist.com/2009/04/09/it-turns-out-that-weird/

It turns out that weird evening bank verification call from AmEx was legit. Brandon wrote back, “After reading all the comments on Consumerist, it stoked my fear of fraud even more, so I called Amex security. They verified the call was legitimate and was from American Express. It was just poor customer service after all.”

Amex Wants To Play "Scam Call" With You, Please Participate

Amex Wants To Play "Scam Call" With You, Please Participate

Update: It turns out the call was legit.