Some info I found in my files from my 2009 trip:
Baggage Airline Guest Services aka BAGS is the fee collection service, NOT the Resort Airline Check-in Desks. BAGS operates seven days a week between the hours of 7 a.m. and 11 p.m. [believe that is EASTERN time] If paying for excess luggage fees through BAGS you must pay with a credit card: MasterCard, Visa, and American Express are accepted. Resort Airline Check-In desks are unable to collect luggage fees on behalf of the airlines.
For ALL airlines, luggage must be 50 pounds or less in order to use the service and it must comply with their airline's size dimension baggage policy. Overweight and oversized luggage cannot be accepted at the Resort Airline Check-In desks.
* Service is separate from Magical Express. You do not have to participate in Magical Express to utilize Resort Airline Check-in Service.
* Each Disney resort has a dedicated Check-In Desk located in or near the Lobby or near the outside entrance to the resort. If you can't
locate the Resort Airline Check-in Desk, ask at the Front Desk.
* Desks are open every day from 5 a.m. to 1 p.m. You can check in no more than 12 hours and no less than 3 hours prior to scheduled flight departure time.
* To check in, your entire party must be present [that was not the case during our stay - son-in-law was able to check in luggage for both self and wife since she and baby were still sleeping so exception MIGHT be made]with your government issued photo I.D. (e.g., driver's license, passport, Military ID) and your Key to the World card to verify you are a guest of a Disney hotel.
* Resort Airline Check-In desks can provide some of the same services and information as airline ticket counters at airport, including checking seat assignments, and verifying flight information and status. Resort Airline Check-In Desks cannot make changes to flight arrangements or new flight reservations.
* Not provided by Disney. A 3RD-party company approved by Transportation Security Administration (TSA) operates Resort Airline Check-In on behalf of participating airlines. [We definately tip these people - it is the same as the sky cap at the airport - they are saving us a lot of time and effort by properly tagging and getting our luggage to the airport and that is worth a tip IMHO!]
* Some persons have reported a wait of over 30 minutes at the Resort Airline check-in desk during peak times. [used service 2 x and took our bags done very early in the morning - all went quickly] If you are within 3 hours of your departure time, you should bypass this service and get your boarding passes at the airport.
Hope this information helps.