I really really doubt this, openai said recently that ai detectors are pretty much impossible. And in the article they literally use the wrong name to refer to a different AI detector.
Especially when you can change Chatgpt’s style by just asking it to write in a more casual way, “stylometrics” seems to be an improbable method for detecting ai as well.
openai had their own ai detector so I don’t really think it’s in their best interest to say that their product being effective is impossible