While I think your story is entirely plausible, I wonder if there could be something else going on. Maybe ChatGPT puts the prompt (or an assumed location) in the image's metadata?

Not ruling it out, but this would mean both ChatGPT to put the metadata in the file, and then Midjourney read that metadata and put it into the img2txt output. (Midjourney produces 4 sets of text outputs from the single input image, two contained location information, naming the specific mountain chains it "saw" in the caricature image.)

Assuming it's not the metadata, it's a powerful use of AI, but also not one that I would not be too surprised about. It can be a useful investigative tool, or simply a fun way to hide clues for a puzzle.