When I was a teenager, I heard the Halloween horror stories, including the horrific razor-in-the-apple ones. Andrew Cline at the American Spectator, citing the work of Joel Best and Gerald Horiuchi--I don't know the latter, but I've read some of Best's work and I think highly of it--writes that they were never true:
Starting in 1969, tales of Halloween horror took a suddenand unexplained leap in the public consciousness. Researchers Joel Best and Gerald Horiuchi, writing in 1985 in the journal Social Problems, found that from 1969 to 1973, America was awash in stories of terrifying Halloween-night sadism. All the now-familiar crimes were reported -- razor blades in apples, poisoned kids, sexual assaults and abductions, you name it. Many were reported inmajor newspapers, including the New York Times. . . .
In their 1985 research, Best and Horiuchi found that not a single story of Halloween sadism was true. No child in America had ever found a razor blade in his apple. There were no random poisonings, and there was no increase in assaults, abductions, tortures, kidnappings, or anything else. The tales were all hoaxes.