I always thought it would be fun to prepare a totally bogus calculus lesson, go over it with kids and have them practice giving bogus answers and then invite the Principal in to observe. The Principal would probably have no understanding of what was being taught but would be so impressed by the kids enthusiasm, participation and engagement she would write up the lesson as one superior to any she had ever seen. Imagine her embarrassment when someone reading the write up caught all the errors.
We had a Principal many years ago who would have observed a calculus class like the one mentioned. But, before doing the write up, he would go to the AP of the department and check the facts. The AP in those days was a real mathematician and nothing got past her. None of those administrators are around anymore. The Principal would be in deep doodoo having to rely on a cabinet member for help.