ChatGPT and the like are in a weird position at the moment. It's usually pretty clear that you have written it using an LLM, but it's hard to PROVE. And you need to be able to prove it (to some degree, which varies depending on the institution) to reliably count off for it, otherwise the student will challenge your finding that they cheated and the Honor Court (or administrator, or other equivalent) will tell you that you can't do that.

So, you can usually get away with it if there is not some way the professor/TA can prove it.

As things change, this will change, but that's the situation the author of the original article finds themself in, because it's the current situation.