Just double checking my understanding: If this is true then only Anthropic will be able to detect if text was generated by one of its models, correct?
Seems like this would only catch the most unsophisticated cases.
You are just pointing out the very visible single cases. But the mass of low-visible content is much higher and more dangerous (like propaganda bot-farms). If a social media platform adds watermarker checks the bots would implement bypasses ASAP.