Yeah, I'm flying Southwest as well (on the way there. Flying Delta back) and I had already checked to see that they participate. Seems like most of the carriers I would fly out of here in Houston do! And it will be nice having it delivered to the room, since I land at 9am. I will stop at the Pop desk to reset my pin and confirm which card I have registered to the room, but soon after that, it's off to EPCOT/Boardwalk to pick up my credentials.... and hopefully make it to Frozen Ever After in time for my 12:15-1:15 fastpass.