You're misunderstanding. I was responding to the idea that simply shutting of the mains will protect from burst pipes. It wouldn't; all it would do is trap the water inside the existing pipes with no outlet. Completely draining (and potentially backfilling antifreeze into sumps) will protect pipes however but that was not what was being suggested by my reading. That said homeowners in this sort of situation may not have pipes built to completely drain anyway; nor would they necessarily want to as that would have a negative impact on sanitation.