From the Wall Street Journal:

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 Smarties.

That was a wacky idea, but we bought it. We still buy it, even though Joel Best, a sociologist at the University of Delaware, has researched the topic and spends every October telling the press that there has never been a single case of any child being killed by a stranger’s Halloween candy. (Oh, yes, he concedes, there was once a Texas boy poisoned by a Pixie Stix. But his dad did it for the insurance money. He was executed.)

Anyway, you’d think that word would get out: poisoned candy not happening. But instead, most Halloween articles to this day tell parents to feed children a big meal before they go trick-or-treating, so they won’t be tempted to eat any candy before bringing it home for inspection.

[…]

Then along came new fears. Parents are warned annually not to let their children wear costumes that are too tight—those could seriously restrict breathing! But not too loose either—kids could trip! Fall! Die!

Treating parents like idiots who couldn’t possibly notice that their kid is turning blue or falling on his face might seem like a losing proposition, but it caught on too.

Halloween taught marketers that parents are willing to be warned about anything, no matter how preposterous, and then they’re willing to be sold whatever solutions the market can come up with. Face paint so no mask will obscure a child’s vision. Purell, so no child touches a germ. And the biggest boondoggle of all: an adult-supervised party, so no child encounters anything exciting, er, “dangerous.”