Imagine trying to pitch this idea today.

Trick or Treating

Trick or treating originated with olden Celtic festivals of Samhain and Calan Gaeaf customs. You would disguise yourself as a fairy or spirit in order to ward off the evil ones. The spirits were active and had to be warded off somehow, and specifically on a more supernatural night like the end of October. Near the 1940s, it regained popularity (as it had fallen out in more recent times) and developed into a thing for the children to do. Going from house to house and getting either sweets, or a nasty surprise!