Enter the Red Queen.
"Eric Mitchell, a graduate student at Stanford University, figured a classifier would take a lot of training data. Along with colleagues, he came up with DetectGPT, a “zero-shot” approach to spotting the difference, meaning the method requires no prior learning. Instead, the method turns a chatbot on itself, to sniff out its own output."
https://www.ft.com/content/e34c24f6-1159-4b88-8d92-a4bda685a73c