I've had a couple of TAs who I strongly suspected of being chatbots, even when I was talking to them in person. I'm still not 100% convinced they were human.
Another thing is foreign students and teachers who, even if otherwise competent, quickly get one used to language comparable with machine output. I think I may have been guilty of that at one time :)
Next step will be to replace the prof, and then have the students replaced by surprisingly attentive interrogative expert systems, and the cycle will be complete.
In fact, that's one way to pass the Turing test: any judge that suggests a subject is bot, experiences a permanent loss of social status regardless of correctness!