It sounds like they are paying extra for a little bit of convienence. In reality all of us can already have a special "reserved week" if we want it.
If you want the week of June 15 for example, then get on the computer at 2 AM 11 months before that week opens and book it. Then, if you want you can cancel it later, try to change it to another resort at the 7 month window, or keep it an go on your trip.
It really is no different than these "pre-reserved" weeks except that you don't have to be on-line at 2 AM on a specific date and yes, for uber-popular weeks there is a slim chance that even being on line exactly 11 months out will not get you that week.
-dave