As of right now, it's being offered at the value resorts only. After speaking to the RAC employees at BW in Dec, I can understand what the holdup is. If SW were to add RAC availability at all Disney resorts, the amount of addtl luggage would be astronomical. From what the RAC people said, SW handles the largest bulk of the checked luggage coming from WDW resorts. If they were to be participating at all resorts, it may very well change the timing involved with checkin proceedures. As it stands now, you have to be completely checked in no less than 3 hrs before your flight departure time. But...if there were to be a huge influx of bags, due to SW's participating everywhere, they might have to change that from 3 hrs to 4 or even 5 hrs!!! Holy Cow!!!!
I'm sure that at some point SW will be 100% participatory....but no one knows for sure when that will happen.