Why it happens is secondary to the fact that it does.
> The models all have disclaimers that state the inverse. People just gradually lose sight of that.
Those disclaimers are barely effective (if at all), and everyone knows that. Including the ones putting them there.
I see all kinds of people being told that AI-based AI detection software used for detecting AI in writing is infallible!
You want to make sure people aren't using fallible AI? Use our AI to detect AI? What could possibly go wrong.