Outbuildings such as the WL cabins and the Poly bungalows are certainly more apt to sustain damage than the main buildings, but I think there's a bigger problem than people in the outbuildings wanting to wander around. Those people have to go somewhere for food and other services. Yes, they might have food in the fridge, but what if they run out? Or what if they get cabin fever? The main buildings enable people to sleep, eat, and even be entertained all in one secure building. Also, CMs then don't have to go outside to the outbuildings to check on guests or take supplies to them. So it's better for guests and for CMs to have everyone in the main building.
BTW, has anyone heard whether Disney is offering special rates to Florida residents for the next few days? I have a friend who took shelter at WDW during a big hurricane about 15-20 years ago.