I know I was being a little harsh - it's impossible to always wear a PFD. And like you said, when I do open water swims I don't wear one (I'm a triathlete, so I do these with some regularity).

That said, I live on Long Island, NY, where even when the water is considered "warm," it's pretty cold. When I do an ocean swim, I'm usually wearing a wetsuit, which provides some additional bouyancy. I'm always amazed at how many people are out on small boats without wearing PFDs.

I do water rescue with the local rescue squad. It is not at all uncommon for us to be out in our 28 foot boat, all kitted out with PFDs and survival suits, and pass an open, overloaded 16 foot center console with a full family on board, with nobody wearing PFDs. It makes me mad.