Lara - that is a different plan for teaching that I've heard of, but makes sense in that you would want them to know what to do if they unexpectedly fall in. I bet it would be strange to see little ones that young without their parents in the pool. I don't know if I (as the parent) would be that brave.
We haven't done this yet, but may see if we can at some point. Just need to find a place that offers weekend hours that isn't too terribly expensive. I'm sure Mark will love it, he's such a water baby now and loves to play in the water.