How tragic - CNN had this article this morning about a boy that drowned in the pool on the Carnival Victory.
Florida boy, 6, drowns in Carnival cruise ship pool - CNN.com
I think half of the problem is that most people do not recognize the symptoms of a person in distress in the water, and in most cases, people (children) do not gasp for breath or start flailing in the water - they go limp and quiet.
I read one story on the internet where a family was on a snorkeling trip, when the Captain of the boat noticed a girl in distress less than 12 feet from her family. He jumped in fully clothed to rescue her, and while he was swimming towards the family the parents were calling "We are Fine!" and the Captain yelled "MOVE !", they got out of his way, and to their shock/horror and ultimate relief, he went under, and pulled the daughter to the surface. The girl then started crying "Daddy!".
That story opened my eyes as a parent. I had it all wrong myself.