Parent of two kids that have used swim diapers. I would be very surprised if those diapers were even 10% effective. Out of the pool they're basically 0% effective.
And yes, I've read the instructions, and spoken to the folks who run the pool.
Mostly I think they're just there to keep the poop in long enough to get the kid out of the pool.
Sure, but it's not always obvious when a kid wearing a swim diaper poops. And they don't always tell you. Especially if they know it means they have to get out of the pool to change the diaper.
Swim diapers basically keep the _turds_ stationary. Water will still chew away at it and disperse poop everywhere, so its basically run out of the water when an "accident" happens. Still better than solid poop floating around I guess, but also, potentially, really nasty.
And yes, I've read the instructions, and spoken to the folks who run the pool.
Mostly I think they're just there to keep the poop in long enough to get the kid out of the pool.