As a certifiable whacko nudist, I would like to add one more point to your highly scientific observations.

Sure, going to the beach is great—but some of the afficionados of bare skin go farther: we maintain clothing-optional homes. When guests come to my apartment for the first time, I politely explain that they are free to shed as much of their attire as they wish—and when (if!) they come a second time, I will be their naked host … a fair and friendly warning. Now, in what is clearly more evidence that skin lovers are perverted beyond any hope of redemption, some of my returning guests step through the door and begin to rip off their duds in an enthusiastic contest to determine who appears first—Naked Guest or Naked Host!