See it was Superhero Day, and they chose to dress up as "Captain Underpants" of children's fiction fame.
Despite the fact that they were obviously not nude, (they wore flesh colored body stockings under the underwear, and a red cape) the principal said "But the appearance was that they were naked." And told them to change or be sent home. They went home. You go girls. What's the big freaking deal? I think Michael K said it best with his comment: it could’ve been worse…they could’ve dressed up as Rambo and shot everyone.
Hmm, maybe I should do that for Halloween...
(dress up like that, not shoot everyone)