He was using a dozen obvious ChatGPT-isms. So either he was lying about writing it manually (the comforting option), or he actually writes like that, which is what I meant being concerning.

But yeah, there isn't a way to prove it one way or the over, even when it's "obvious".

I saw in some schools they're using systems where you have to type the essay in a web app, and the web app analyzes your keystrokes to determine if you're human.