So what about the case of the electrocuted girl? Would bonding the water have prevented the accident from occurring?
Very hard to tell from a Faux News story, but possibly not.
My SWAG is that the wire hit a parking lot drain and energized the whole pool drain system (not properly bonded!) That raised the water to the level of the fault voltage. A conductive pool shell almost certainly would have helped. A water bond close to the ladder might have helped.
A proper bond between the ladder and the water supply and drain piping almost certainly would have prevented the tragedy with or without a water bond.
The water bond really only comes into play when the plumbing is all non-conductive and a single live conductor falls into the pool. It will take a low impedance ground to trigger any OCPD, and it will take good bonding to prevent the touch potential.
The lifeguard who told the swimmers to get out of the pool made the biggest error in judgement, but cannot really be blamed for that.
I strongly suspect that when all is said and done, it will be determined that the bonding (not including water bonding) at the pool was incorrect originally or had failed
All that from little or no information, of course.