I tried the link and used my Marriott #. "Your account number is not part of this exclusive promotion". Used my wife's and she got registered. "Simply use your Marriott Rewards Visa Card". I got her a card awhile ago and only used it to get the signup bonus. Never used since then.

With the AMEX Promo (And ?? unknown/month) will only be using the AMEX thru January.

I just wonder what whould happen if I reserved under her Marriott account and used MY Visa card to pay. I am guessing that she would not get the double bonus.