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 this is a dead giveaway you're not a parent, or have never dealt with swim diapers :)
Swim diapers are designed to simply make sure the poop and the kid are in the same general area and that it's easy to remove them from the water as a self contained unit. It will still absolutely contaminate the water in some way, there's no escaping it.
Poop can still leak out of swim diapers. After going to swim lessons with my daughter and a dozen other 6-month-olds at the local YMCA, I understand why it is so heavily chlorinated.
I wish they would ban swim diapers altogether. You never know what's in there, there probably is something, if the parents see the necessity. Just ban child and parent for a month if they can't hold it and spoil the pool for everyone.
Children who do not have proper bowel control yet are out of place in the public pool. Why should people have to put up with someone else's faeces? It's not hygienic.
There are some really nasty diseases that can spread through human waste, and I would not want to come in contact with them.