The man in question is not a stupid man. He's president of a business many in here would recognize. I suppose he either didn't think it was necessary or didn't think about it at all. I'm not going to berate him, I've certainly done a dumb thing or two in my life, but he did make a series of poor decisions which added up to a cold (and expensive) swim (and night out) that could have cost a few people their lives.
Interestingly, the author of the article, under the heading "Lessons Learned" had the sentence "Oh, for a survival kit when you need one. Of course even if they had one, it's entirely possible the men would not have salvaged it in time: planes are made to fly, not float."
Again, I'm thinking: Small plane + over water = survival VEST - worn on your body - at all times. It will leave the aircraft at the same time you do. Maybe ask your passengers to wear one too.
Floatplane rating, anyone??