In the 2004 teen comedy "Mean Girls," Lindsay Lohan's character, Cady, who just moved to the United States from Africa, observes that for American girls, Halloween seems to be nothing more than a day when girls can dress up in scandalous outfits and no one can say anything about it. When mean girl Gretchen asks her friend Karen, who's barely clad in black lingerie and animal ears, what she's supposed to be, Karen points to the ears and says, "I'm a mouse. Duh." The idea of sexy Halloween is not necessarily a new one. For years, Halloween parties have had...