Halloween is the day when America market-tests parental paranoia. If a new fear flies on Halloween, it's probably going to catch on the rest of the year, too.

Take "stranger danger," the classic Halloween horror. Even when I was a kid, back in the "Bewitched" and "Brady Bunch" costume era, parents were already worried about neighbors poisoning candy. Sure, the folks down the street might smile and wave the rest of the year, but apparently they were just biding their time before stuffing us silly with strychnine-laced...