You also get 5,000 miles for adding an authorized user for any of these offers. (rewardexpert.com)
Also, get 5,000 points when adding an authorized user to the account. (doctorofcredit.com)
Note: you could also earn 5,000 additional points for adding an authorized user who makes at least 1 purchase during the first 3 months. (richmondsavers.com)