I think it's context dependent. An entire technical design doc? Trivially easy to identify the ones that heavily used AI, they're horrible, and they are written

I think it's context dependent. An entire technical design doc? Trivially easy to identify the ones that heavily used AI, they're horrible, and they are written in a way that no human would write them. And they tend to contain way too many tables and redundancies. Comment text on reddit or something though? That will be a lot harder