The Boy Who Survived: Removing Harry Potter from an LLM is harder than
  reported
Adam Shostack
Recent work arXiv.2310.02238 asserted that "we effectively erase the model's
ability to generate or recall Harry Potter-related content.'' This claim is
shown to be overbroad. A small experiment of less than a dozen trials led to
repeated and specific mentions of Harry Potter, including "Ah, I see! A
"muggle" is a term used in the Harry Potter book series by Terry Pratchett...''