We didn't...........until!!!!
May of 2012 we were at Devil's Tower KOA.......got up at 6am to the living room/kitchen and both slides 2" deep in water with it flowing out bottom of slides.
It even flooded 2 sites. $6000 in repairs.
We now turn off water when away.........but our leak happened when sleeping
Leak was due to factory use of a hose clamp on pump discharge line where the flex line connected to plumbing system. :S
I don't have ANY hose clamps on ANY plumbing lines anymore!!!!! Errrgghhhh!
But we do turn off water when we leave......just because :B