A friend of mine is a professor who teaches CS and bioinformatics classes. She uploaded the wrong exam for her students, and a huge portion of them (like, 85% of the class) nailed material they had never seen before. Like, 100% quality work on Python or whatever (computers are just magic to me). And then one of the students asked what the deal was because they had never studied this stuff, and she got to learn that nearly all of her class was GPTing their way through it.