this is the most stupid advice.
WEAR A LIFE JACKET.
5 rowers lost their lives because they did not wear LIFE JACKETS.
http://news.asiaone.com/News/AsiaOne+News/Singapore/Story/A1Story20080530-68014.html
Life jackets are not foolproof. People have drowned because the jackets slipped off or because they panicked when they fell into the water.
There are also many cases where people have drowned because they fell into deep water by accident.. eg hit by a wave or fell off a pier. You don't put on life jacket when you're taking a stroll by the lake.
Swimming is a basic life skill that everyone should learn the earlier the better.