"Swim Nude to Prevent Sea Lice Infection." Such was the recent headline in a U.S. Public Health Service professional journal. Skinny-dipping is not naughty; it's healthy, experts say, referring to the rash that generally appears on bodies covered in swimsuits. You see, the microscopic jellyfish get trapped beneath the material and release a skin-irritating venom. If that doesn't scare the pants off you, then forget this advice: Peel off your duds behind the Marriott hotel on A1A, scurry across a private beach (though we have had no trouble running around nude for nearly an hour around midnight on several occasions), and give the moon to the night sky.