The girls from W.I.T.C.H. lose their clothing when they transform into guardians. Though they curl up in fetal postitions, it's quite clear they are following in the tradition of magical girls who "go natural" during transformation scenes.
Now here's a freaky piece of trivia: The original design for Looney Toons' Tweety had no feathers, like he was just hatched. Warner Brothers' censors made the animators change that because they thought a bird without feathers implied nudity. But for over 60 years, none of them have noticed that Porky Pig doesn't wear pants. Nor does he have the "fur and feathers" excuse used by Bugs, Daffy, Foghorn, Wile E., etc.