The CM I talked with this a.m. when booking my reservation explicitly warned me that my reservation is NOT guaranteed until a deposit is received. She stated that they can AND HAVE (just this weeked for some Visa holders!) cancel out any reservation OVERNIGHT that has not had a deposit applied.
I too was counting on holding my reservation off for a week, but I'm too nervous that I'll lose my resort. I'm scrambling trying to get the deposit paid by evening today!
Wish me luck and best wishes to all!