FYI - registered the credit card I use for Mileage Plus Dining with Marriott's new program, and instantly got an email:
"We're so happy you've been enjoying dining with us. We noticed that you recently moved a credit or debit card to another dining program.
Each card can only be registered in one dining program, so you will no longer be earning MileagePlus® award miles with that card ".
So that answers it
