If the algos work as advertised, watermarked token sequences have an extremely low probability. Copying the words by hand doesn't change that.

The mechanism seems to survive editing. The extreme probabilities get a little less extreme, but are still extreme enough to be distinctive.

But it wouldn't survive paraphrasing, because the output would be entirely human and the token correlations would disappear.

It might not survive referencing if only a sentence or two is used.

The practical issue is how true the claims are. It's one thing to create a proof of concept, another to see how it works in use.

And this is potentially catastrophic for code, because the grammar and word choices of code are completely different and more fragile than standard English.