It is a simple matter of supply and demand... if guests are requesting to stay in certain buildings more than others, it stands to reason that these rooms must be "preferred" over some others, for one reason, or another. Since this is the case, and not everyone can stay in those buildings, they charge an extra $10 a night to those who really want to stay there, and those guests will willingly pay the extra. Makes perfect sense, and as long as there are people out there willing to do so, then by all means, Disney is being very business savvy by taking advantage of it. Really it is no different than wanting a room with a pool or water view at one of the mods or deluxes...it is all in what the guest wants and how much they are willing to pay.