You can always ask at check in....I am sure occasional complimentary upgrades do happen, but I think they are few and far between....more commonly if you ask about an upgrade to the tower they will check and if a room is available they will offer the upgrade for a fee....and it usually the exact same difference between the wing and tower rooms at the rate you booked (usually $60 to 80/night or more)...complimentary upgrades at the CR are usually reserved for guests purchasing non-discounted packages. What does happen more commonly is a complimentary view upgrade in the wings (i.e., if you have booked a standard view wing room you are much more likely to upgraded to a water or park view wing room than a tower room).