tinfoil had theory: they implanted watermarks already, so that AI generated text can be flagged for future training runs or as a service, such that some phrases are coaxed to become statistical beacons.
That's not really a tinfoil hat theory. That's been possible for some years and OpenAI reportedly does watermark their outputs, and can detect it. They just haven't released it as a service because it'd annoy all the users who are using it for cheating :)