One thing to add on this. We had everything linked up and none of our bands worked last year, but the more I think about it, we had a 2 bedroom with 6 people staying in it. 2 of the people in the room did not have MDE accounts (we just had them on the reservation), but the other 4 all had bands. When linked at
DisneyAulani.com, it just shows generic accounts for those folks (with no avatar, etc.), so they didn't have bands. I wonder if that affected the rest of the room.
Of course, that said (and this was last May), when I went to the front desk to ask about it, they just adamantly insisted that they didn't work at Aulani (even though numerous folks here were able to get them to work...). It was all very frustrating, but we just made due with the cards...