If you need a room for disabilites Guaranteed the Special Needs department at Central Reservations can do that for you. If you are just requesting a king bed it wouldn't hurt to say it was for medical needs, but it is still just a request...Unless you are staying at a Moderate resort (Coronado Springs, Caribbean Beach, Port Orleans French Quarter or Riverside)... Moderate resorts have king bed rooms as a dedicated category of room, so at any of those you could "Book" a King bed room rather than just "request" one.