Sure enough the NCVT alerted from 2 feet away since there was a 120-volt potential on the chassis with his grandchildren spraying it with a hose. He's now one of my most vocal supporters in the RV industry since he could have killed his own grandchildren. And now he knows to never be washing an RV while it's plugged into shore power. That's just asking for trouble. You can also get voltage gradients in water puddles that will reach out dozens of feet from the fault source.
So at a water park, carry and use a NCVT and check the place out for any signs of a lack of maintenance, or shortcuts.
Years ago I worked as a field service tech. My field didn't involve amusement parks but it made me aware of how little customers understand or care about maintenance. I would look the rides over very carefully looking for missing bolts, or even pealing paint. I attend a lot of antique tractor shows. I enjoy seeing the steam traction engines. The first think I look on each one is the water level. Once I know that is correct, I can enjoy looking over the machine.