This is actually kind of genius...apparently some parents tell their kids that on Halloween, you can leave the Switch Witch some (or all) of your Halloween candy (which she apparently needs for her "potions") and in exchange, she'll leave you a small toy or craft or even a gift card for Target or Starbucks or some other age-appropriate store (like Ulta if your kid is, like, 9...)
It's not quite as genius (IMO) as the parent who left a comment saying they take their kids to ALL the truck or treat or trick or treat street events, make them surrender a portion of the candy they collect and then pass that candy out for Halloween. Now THAT's genius!