I recently did an upgrade for my brother at Costco 3 months ago and it's just like Verizon handles them. He had a 2 year upgrade ready in our plan, I'm the main line so I went in and signed a new 2 year contract for his number and got the upgrade phone price (brought his Droid Inc2 down to like $69).
Now, with their crazy bundle deal, with all the accessories/docks, I just don't know how that will work. I still don't believe they're going to be doing all that and the Bionic for $299, it just seems too good to be true.
That's like $600+ in value and I don't see how it works out for Costco, since it's Verizon who will be the ones benefiting from your new 2 year contract.