I just did the same thing. Booked 2 WL rooms for Sept. and they booked us 1 ressie with 2 rooms on a AAA discount ($169/nt) They didn't want the number but indicated that the AAA card must be shown at check-in. I think it doesn't matter if the other person is a member or not, the ressie is for 2 rooms under your name, so you're responsible for paying.