^^^This story reminds me of something. Why did schools (or at least my school) mandate you wait 10 minutes for a teacher (15 minutes for a professor) before you are allowed to assume class is cancelled and leave? What's more, if the teacher shows up more than 15 minutes late, why are they allowed to shove you back into class and continue? If I'm more than a second late, I get points marked off, or not even allowed into class at all. If they are supposed to lead by example, why can't we say, "Too bad, you're not here so class is cancelled for today?"
(I know it'd never happen, and there'd be material lost, but it'd be nice.
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