Not only that, but the bodies wearing the least are the ones I want to see the least (Photo on the right notwithstanding).
Seriously, what's the deal? The only possible explanation I can think of is that when the contestants show up at whatever airport/hotel they are not informed (or are misled) about when exactly they'll be leaving for their final destination. Maybe they're told to leave their luggage at the hotel because they're being taken on a tour, hence being caught flat-footed. On the other hand, these folks do have clothes with them, the stuff they arrived in.
What I'm wondering is what the producers would have done if some of the women arrived wearing thong underwear or sheer bras?
In any case, future contestants, take note: When you get on the plane in Los Angeles, be wearing a bathing suit under your clothes and as for clothes, have on everything that you are planning to take with you to the island.