In one of my classes, when ChatGPT was still new, I once handed out homework assignments related to programming. Multiple students handed in code that obviously came from ChatGPT (too clean a style, too general for the simple tasks that they were required to do).

Decided to bring one of the most egregious cases to class to discuss, because several people handed in something similar, so at least someone should be able to explain how the code works, right? Nobody could, so we went through it and made sense of it together. The code was also nonfunctional, so we looked at why it failed, too. I then gave them the talk about how their time in university is likely the only time in their lives when they can fully commit themselves to learning, and where each class is a once-in-a-lifetime opportunity to learn something in a way that they will never be able to experience again after they graduate (plus some stuff about fairness) and how they are depriving themselves of these opportunities by using AI in this way.

This seemed to get through, and we then established some ground rules that all students seemed to stick with throughout the rest of the class. I now have an AI policy that explains what kind of AI use I consider acceptable and unacceptable. Doesn't solve the problem completely, but I haven't had any really egregious cases since then. Most students listen once they understand it's really about them and their own "becoming" professional and a more fully developed person.