As children go trick-or-treating, it is exceedingly unlikely that your neighbor will put a razor blade in an apple, poison a wrapped Snickers bar, or, in this year’s version of the same old story, swap THC-laced gummies for regular candy, tricking innocent youngsters into accidentally getting high.

Historically, such acts have not just been rare, but very close to completely undocumented. The lack of evidence has done little to reassure parents, the police and some in the media, who have repeated the mostly unverified claims for decades.

Typically, the warnings come before Halloween, instructing parents to inspect their children’s haul for any signs of foul play. In recent years, with marijuana becoming legal in more states, the concern has shifted to children accidentally ingesting edible weed candies, laced with THC and designed to look like traditional snacks. “A different sugar high: Bensalem police warn of ‘weed candy’ this Halloween,” read one headline from Pennsylvania this month.