I got one of those emails from a student the other day, explaining that s/he was going to be away for a couple weeks during the semester, and hoping that we would be able to work out an arrangement so s/he could do the classwork ahead and such.
My first reaction is to wonder why a student makes plans to be away for two weeks during a semester. The thought it alien to me; it's just something that seems so impossible.
My second thought, though, is to wonder why I'm so rigid about this sort of thing. I can think of numerous things I've missed out on in life because I just thought I wasn't allowed or shouldn't do it. And then later I find out that someone else did it, and things worked out.
One problem is a sort of Kantian dilemma: if every student takes off for two weeks during the semester, we'll have problems holding good discussions (this is an upper level seminar, and not a class where one lectures or something). But that's never going to happen, right? Even if every student did it at some point in his/her career as an undergrad, it wouldn't all be in one semester. It's the sort of false dilemma that I tend to use in my rigidity to make sense of saying "no."
And it's not like the world is going to come to a stop if someone's missing. I know a lot of faculty members who just don't miss class, even if we're pretty darned sick, because we feel like we're the center of the class and that it can't really happen without us. But things can happen without us, and even if they don't, missing a day of class won't bring the world to a stop.
For so long now, I've arranged my life in terms of the academic schedule that I don't question it, though I should.
I have to think about how to make this work because it really is a special opportunity for the student, and the class isn't going to come to a total stop because s/he's not there for a couple weeks. On the other hand, I do think class is important or I wouldn't be teaching it. The class isn't a hoop to jump through, but something that I really try to make meaningful every single day.