Jamir Nazir won a Caribbean regional prize at the Commonwealth Short Story Prize. 7,806 entries. One winner from his region. Days later, online commentators ran his story through AI detection tools and declared it machine-written. Granta's own publisher said the judges may have "awarded a prize to an instance of AI plagiarism." Three detection tools were used. Three different verdicts. This is the new plagiarism charge. Easy to throw. Hard to disprove. Burden of proof falls on the writer. I've been working on this problem: collecting AI tells, reverse-engineering prompts, ghostwriting for people who need to prove their own voice on the page. Here's what I've learned about what actually separates human writing from machine writing. Hint: it's not the em dashes.