The other day there was a thread here about the Earthsea books where some people posted their favourite quotes from the series.

I saw that one of the quotes wasn't actually from the series and asked the user if they'd actually used an LLM to generate it. They confirmed that they had. It would have been easy to miss that it wasn't real. Eventually their comments got flagged (not by me) and hidden, but probably only due to me calling it out.

It does make me a little concerned about the future.