You still have some that control, but in a much more indirect way.

There are three kinds of data now, synthetic, pre-2022 and current. Everything pre-2022 is definitely written by humans, synthetic data is still synthetic, and post-2022 is a mix of both.

I wouldn't be surprised if "AI detectors" work somewhat for this use case. They're biased, far from accurate and a terrible idea if you need to make important decisions (like whether to expel a student for cheating), but there's quite a large room for errors here.