ftnoob, I cannot say that I have done this with this card before, but I have had to do this with other cards when I did not get a bonus that I thought I had signed up for and it has worked everytime I have had to do it so give it a try, your friend has nothing to lose. When you get your first statement and see that you get your 8 RR credits, call into customer service and tell them that you should have gotten 16 because of the promo that you used when you signed up. They should transfer you up to a manager and if they don't, ask to be transfered anyway. Tell the same thing to this person, they should know what to do, this is a standard process for them. They should ask you for some verification of this bonus and either offer to mail them the paper mailer with the 16 credit offer or a screen shot of the 16 credit offer that you "clicked through" when you signed up for the credit card (should be easier to get one of these
http://www.southwest.com/bonus). It might cost you a stamp and a few minutes on the phone but this has worked for me with both Citi and Chase credit cards when they shorted me on a sign up bonus. Good luck!