Not really. It's more of a sign that the person knows how to swim efficiently, which I suspect is inversely related to risk of drowning. Case in point: go to a

Not really. It's more of a sign that the person knows how to swim efficiently, which I suspect is inversely related to risk of drowning. Case in point: go to a public swimming pool (YMCA, etc.) when old people are swimming laps. You'll see people who are clearly not athletic swim for many tens of minutes without taking a break.