I've noticed something very interesting here at Duquesne since I started: The students are rarely, if ever, late for class. Why is that?
It's fair to note that my frame of reference is my time spent teaching at WVU, but I think it's unfair to categorize Duquesne students as that much more concerned in showing up to class on time. Similarly, I don't think the incidence of off-campus commuters plays a large role in explaining the difference-- I've had plenty of students at both schools drive in to attend class.
I think it has to do with the fact that most students take elevators to get to class. Elevators introduce a degree of uncertainty into the class arrival time function; most people know how long it takes to walk somewhere, but taking the elevator increases the variance in expected arrival time. I would guess that many students aren't terribly averse to arriving a minute or two late to class; however, these same students may be particularly averse-- in relative terms, if nothing else-- to arriving a few minutes later, say, 4-6 minutes. A sufficiently high enough level of uncertainty in the elevators could push students to arrive early enough to ensure that they never hit this 4-6 minute late arrival.
Then again, there's no reason to believe they couldn't update their beliefs on the elevator through experience. But I think that assuming elevators will be continually uncertain is getting kids into my classes on time.
There's a perfect natural experiment for this, of course-- teach (or witness) a class in another building. Until that time comes, I'm sticking with the elevator story.