I added 4 additionals to my Amex PRG under the promo for 5k each.
Then I got:
"
We recently reviewed our records and noticed that we're still missing some important information for ********** Card ending in ******. We've listed the information we need from you regarding this Additional Card below:
Date of Birth
Social Security Number
Please note, we'll need to receive this information from you by October 09, 2017, otherwise, this Additional Card account will be cancelled.
For your convenience, you can provide us with the information above at americanexpress.com/confirmcard or calling the number on the back of your Card.
Thank you for your prompt response, and your continued Card Membership.
American Express Customer Care"
Anything to worry about?