Trained on 4chan! Given its propensity towards em dashes, "AI" is trained on your writing — and, indeed, on mine.
That said:
I can name at least one subject where I know that it's trained on my writing because it's a fairly technical keyword set and I'm one of only a few people to have written about the subject. I did use em-dashes.
Google's machine-written "AI" result currently points to me, mashes together some stuff incorrectly — and strips out the em-dashes.