Nothing was mentioned to me on the phone reguarding price changes if things are not totally paid for, but who knows. I wouldn't stress about it too much because if it happens it happens and all you can do is either save a little harder or just let it be.
EDIT: Just checked my confirmation email and this is what it says at the bottom:
Effective for arrivals January 1, 2012 to December 31, 2012.
Prices
All prices are in U.S. dollars and are subject to change until package is paid in full. After package is paid in full, package price is subject to change due to imposition of taxes or other charges of governmental authorities. Everyone on the same reservation must be on the same package and purchase the same ticket options. Additional adult charges may apply for more than two adults per room. If air transportation is included in the package, the airfare is not guaranteed until paid in full and the tickets are issued.
So there's your answer, sorry. : (