IIRC there was a case where a professor in the US tried to fail students based on such a detector and they were able to prove via Google Docs Revision History that they had actually typed it themselves. It is also stupid to claim to be able to detect an AI that imitates human behavior, of course at the beginning you can still find patterns that repeat themselves, but at some point they no longer do because the imitation is perfect, especially because speech is not a medium as susceptible to noise as sound, for example.