That's not cheating at all. That's "write your own notes out of your head." It sounds like you found a way to make them learn all the stuff they needed, while your students thought they were learning a shortcut!
Way back in the Ice Age when I was a student, I would occasionally find an exam question that was just plain wrong, and I would argue about it. Students who have the exam ahead of time and can't see SEVERAL of them were wrong have obviously not mastered the material at all. Or else they memorized the answer sequence instead of reading it, which seems just as difficult as learning the stuff in the first place.
I wrote it that way because, while the last egg was refrigerated and not powdered, it was still fairly old. The last supply plane they got was around April, I think.
In the discussion of this article, the Mefite who serendipitously goes by Pink Fuzzy Bunny told a great story about what happens when Hollywood suddenly drains the market of a product they need.
As a peculiar aside, I looked up the proper spelling of livestream (it can be one word or two), and the search results included the question "Are live and live spelled the same?" You can't make this stuff up.