I think its always on the boat to avoid a swimmer, regardless of where they are, but a swimmer way outside any swim area should also pay attention.

Always good to have any crew member who sees something not only yell out what they see, but where and how far - my wife often gets excited if she see's something while we're driving and it annoys me as I often think there's something I need to watch out for, when it turns out to be nothing..

The other story is great - funny what a small world it is!