"So after that, he was like, "I want to take you around and show you a few other places." We were like, "Yeah that's cool; it's not like we've got *** else better to do." I think the first place we went was to see the sharks, which was ***** awesome. You see, there's like one half of Aruba where all the tourists go surfing, and they can't have any sharks over there lest they end up with a Jaws-like situation. So what they do is that they drop ***loads of meat into the water on the opposite side of the island. It's weird because you can go right up to the edge of this little cliff and look over and see mad sharks just swimming around in the water..."
this is from some blog but I can confirm from firsthand experience
Blog or no blog, I think that's what probably happened.
So maybe Natalee did ask to go see the sharks?? (As in the email purported to be from Deepak.) Or maybe she never ASKED to see them but was nevertheless made to make their acquaintance, G-d forbid???