Perhaps LLM outputs are uncopyrightable, but derivative works of copyrighted works are not automatically in the public domain.
Working backwards: if it is possible to confirm 100% confidence that a chunk of text is LLM output, then it is "PD until proven otherwise". How can a human reliably assert human authorship of their source text? When all watermark tests fail? Is that proof of humanity now?
If a human proves human authorship, and LLM watermarking tests positive, then is that going to be considered a "derivative work" or not? What if there is an applicable license for the source work, such as "CC-BY-ND" that prohibits derivative works?
This has not been court-tested, and I expect that it will need testing at that level before we can have any assurances.
As for it being "uncopyrightable" if it were the output of an LLM, I think computer people are making a very aspie interpretation of a single decision. I think it's more that the LLM (and thereby its owners) cannot itself hold a copyright on its output, that output has to be touched by a person before it is copyrightable. A particular view from the top of a mountain can't be copyrighted, for example, but a photograph of that view can be.
I'm not sure it at all precludes a "robosigning"* sort of situation, where machines generate output, hired temps sign and claim that output, and immediately sign it over to the people who hired them (as a work-for-hire.) Copyright is stupid, artificial law, not logical.
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* https://www.mortgageauditsonline.com/what-are-robo-signers/
For the watermark to be detectable, the text needs to be like 75% AI generated.
If you have an LLM “touch” one section of the article, it’s not gonna be detectable.
Here is some text that is copyright to me. As you infringed my copyright, please pay my $5000 license fee for every user who has read it:
> Copyright law was updated in a very helpful way in the last twenty years sometime so that as soon as you post something to the internet you have copyright. If you need a citation don't hesitate to ask someone else.