I have to say that along with Lara, I also have had many a discussion with tourists who feel the need to swim or snorkel way beyond the docks, sometimes even out in the boat lane. I have actually been asked, "Don't swimmers have right of way over the boats?"
I have nervously watched many folks swim way out further than they should, hoping and praying that they make it back safely. I have seen where boats barely miss them and actually turn around and warn them that they are playing with fire.
For some reason folks think they are invincible on vacation.
I should add that I certainly don't know the specifics of this accident. I am just stating that tourists swimming way too far out from the docks is a very common problem.