We stayed at the Hyatt the night before our January 2004 cruise. We did not use Disney transfers. We rented a limo instead. Before we left, I called the Hyatt directly and was assured that we could have our bags transfered even though we had not purchased Disney's transfers. I decided to call beforehand because some posts had stated that the Hyatt would not transfer bags without Disney transfers. When we arrived at the hotel, the porter took our bags at the front desk (we had already tagged them), and they arrived the next afternoon at the ship, just as the Hyatt promised. We are cruising again this January and we're staying at the Hyatt again and using our our transportation. I recently read some posts that again stated that you have to buy Disney transfers in order for the Hyatt to transfer your bags. Therefore, I called the Hyatt directly and was again assured that they would transfer our bags even though we did not have Disney transfers. There really is no secret here. When you check in, the front desk staff gives you a sheet explaining the process. Therefore, even though the Hyatt has become very expensive, we are staying there because it is extremely convenient, e.g. no late night shuttle buses, no hauling bags to our limo, etc.
Good luck and have a great trip!!!!