Funny, just last night I started drafting out a very similar post about Japanese students using ChatGPT to do their homework and how the teachers are panicked about what to do. I'm not sure what I really want to say, so it might remain in my drafts folder for awhile.
But yeah, we cheated too. In grade school it was passing notes, writing answers on our body, or something similar. In university I remember all the bookshops sold prewritten essays, previous tests for every class (as it seemed like most profs at our school were similar to yours and didn't change the tests much from year to year or followed a pattern we had all figured out), and similar things. I'm still not sure how that was allowed.
Students learned more how to cram for the exams at highest efficiency than to actually learn and get a deeper knowledge or interest of the subject.
This is the problem with the current school system. In the US and Japan it is just memorize for the test and then forget after the test. There is no learning. Something definitely needs to change. Hopefully this current ChatGPT problem will provoke the schools to finally change.