I tried an experiment when GPT4 allowed for browsing. I sent it my website and asked it to read my blog posts, then to write a new blog post in my writing style. It did an ok job. Not spectacular but it did pick up on a few things (I use a lot of -'s when I write).

The point being that it's already possible to change ChatGPT's tone significantly. Think of how many people have done "Write a poem but as if <blah famous person> wrote it". The idea that ChatGPT could be reliably detected is kind of silly. It's an interesting problem but not one I'd feel comfortable publishing a tool to solve.