Buy a cattle prod. That tends to cut way back on the kid's splashing.
I read about this every winter. Some folks carry water in a bucket from the house, others have a spigot installed in the basement or garage so they can pull the hose out, use it, and then coil it safely inside again.
I used a tub up in the snow country around Lake Tahoe many years ago - they had one of those freeze-proof faucets (the valve is set way back into the wall of the house but the handle and connection stick out) and there was a 'vacuum breaker' on the faucet. So as soon as you shut off the water, the vacuum breaker opened and the hose began to drain. We took a few seconds to see to it that all the water drained out and left the hose hanging right there. Worked fine for the week we were there...
I am just so glad I live in a temperate climate!!!
8-)