I have had the same experience as Mitch. Accidentally left the pump switch on and found it running at the next stop. Same thing, open a tap, run it a bit, shut off and the pump stops.
But here's one - a totally fluke occurrence:
I left a CG once with a full fresh water tank, and thankfully, empty waste tanks.
Hours later, I stopped and went into the TT, and the pump was running. A check revealed that the grey tank was full, the fresh tank was empty! Huh??
A further search revealed that the bathtub faucet was open, turned on, and there was a bottle of shampoo in the bottom of the tub.
Well, I had forgotten to turn the pump off as I usually try to remember to do. I forgot to take the shampoo off the little shelf above the tub faucet. In transit, it fell off and hit the tap on just the exact place needed to turn it on!
Consequently, on comes the pump and it drained my fresh tank into the grey tank. The grey was full, but it ran out of water before it could overflow.
What are the chances of that happening? Very remote, but it happened.
My opinion is that it is always best to travel with the pump off. You never know what could happen.
