I looked into the video on this... showing its use in a pool. Seems you'd need to walk all areas of the dock to learn if there was elect current any place in the water?? Not very efficient if that is so.
My question...[regarding fresh water]: If you reach off finger dock to rinse hands in water... and there were electrical current in water... would it shock you to death?
Wash your hands one at a time.
Seriously, I can't answer your question with authority but it's the electric current passing through your heart that does the damage. One of the safety rules of working on something that may be hot is, keep one hand in your pocket. Of course that doesn't work if you're standing in a puddle.