I'm a little surprised to hear this since my thoughts would be that the water in the plumbing isn't really sloshing around....maybe the tanks would be..
I just think of the plumbing that is below the floor and in those areas where the furnace is vented to. To me it's a roll of the dice as to when it gets too cold. Personally I'd rather take the safe route and deploy some heat. The penalty for guessing wrong is too great.
Jack