> If he suspects a student of having generated their essay with AI, he will call them up to his desk and ask them to produce an em-dash on the computer.

I'm someone who normally uses a lot of em-dashes in my writing, but I'd be hard-pressed to generate one at a keyboard. I normally write them as "--", which the word processor automatically converts to an em-dash. I hope the author is aware of this and allows the student to demonstrate using the word processor that the student normally uses.