Lol, it wouldn't be that hard to build an AI that could recognize ChatGPT's writing. I mean, it's not like ChatGPT is producing some super unique and creative language or anything. It's just spitting out the same old generic responses to prompts. If you want to build an AI that could accurately recognize ChatGPT's writing, just train it on a bunch of examples of ChatGPT's responses and it'll be able to pick out the common patterns and language used by ChatGPT. Easy peasy.
(Prompt: Respond to the above in the style of 4chan, but use punctuation.)
Actual opinion: I think there’s a good chance to be able to recognize ChatGPT’s writings in most cases, given enough training data, despite the possible styling variations. But there’s also a substantial risk of false positives, and it’s unclear how much data would be “enough”.