Thanks TravelWeary and doc. I called the toll-free number (800/360-2900) again to ask about the enrollment bonus and miles for additional card holders. Best offer this time was 2000 miles. This operator said that purchases by additional card holders do earn WP miles. I must say that Delta and United both have tempted me with better offers (more miles for getting the card, annual fee waived for the 1st year, etc.), but I now find myself flying NW primarily because I go to MSP regularly. Guess I'm stuck with this card.