Related side story from a former annoying student:
My high school chemistry teacher had a great system for homework. It was AP chem II, and widely considered the hardest course in the school. It was optional, and only the truly devoted (or the children of truly devoted parents) would take it. Your grade was based on three things: 1) labs, 2) unit exams, and 3) daily homework. During the one- or two-week-long unit, the teacher would assign the homework on the unit subject almost daily. But he wouldn’t collect it. Unit tests would be on Thursdays, and he would have them graded by the following day. If you scored below an ‘A’ on the unit test (i.e. 89% or worse), then he would, at that point, collect your pile of homework for the unit. If you had gotten an ‘A’, he would give you full credit for it, sight unseen, and you could toss it. Or, if you were me, you would breathe a sigh of relief, because you hadn’t done any of it. See, I always had a really good grasp of the material without doing the outside homework, and could almost always swing an ‘A’ without it. The teacher absolutely didn’t care: if you got the material without doing the work, then his job was done. Why should you be forced to do useless busywork?
It was a thrilling gamble for me though. I always knew the material well enough to get between 88 and 94 percent on the exams. I ran into trouble when I got an 88 though, which happened fairly often. An 88 on the exam would mean I’d have to produce my homework, and since I’d rarely done much of it, that meant I’d lose a huge bundle of points. There were 50 questions on the exam, so I always had to convince him that one of my incorrect (multiple choice) answers was actually correct, or that two of my incorrect answers deserved half credit.
I could usually talk him into it. In retrospect, it’s hard to say whether I was just absolutely insufferable and he wanted me out of his office, or whether he’d give me the points because he could recognize that I truly knew the material and was passionate about the subject. I’d go in there and explain why MY answer absolutely made sense, and the correct answer, while still a very good answer, was not really a very good analysis of the question that he’d written. I’d explain that the more common isotope has this orbital hybridization; or I’d drag him out into the lab and show him how, empirically, this precipitate does form when using the school’s chemical supply. I always got a thrill testing whether I could talk him into my way of seeing things.
Now I’m a trial lawyer. Go figure.