In 2003 we were staying at the Mission Bay CG in San Diego. Our neighbors behind us had a new Fleetwood Revolution, really nice rig and really nice people. Good grief I even remember their names - Tom and Penny.:B They were gone one afternoon and I heard water pouring down from their service bay door. I shut the water off at the faucet and told him about it when they returned. He had been using the outside shower to rinse something off and when through had shut it off at the outlet nozzle instead of shutting off the individual knobs. Over several hours of being under pressure, the nozzle head blew off and spewed water. No damage other than having to reattach the nozzle, but just another instance of what can happen under pressure.
No, I don't usually shut the water off, but I should. For the most part, I am dry camping and try to never leave the coach with the pump turned on.