I have no doubt they can benchmax their way into believing the differences caused by watermarking are imperceptible. But I'm skeptical there won't be a drop in

I have no doubt they can benchmax their way into believing the differences caused by watermarking are imperceptible. But I'm skeptical there won't be a drop in quality that puts them at a disadvantage relative to competitors that don't do this. This adds a new constraint changing predicting the next token to predicting the next token that carries the watermark. It's hard to see how this can avoid making the watermarked output <= the desired output in quality.