Why can't I smoke in a classroom?

Why can’t I study in a classroom? [3585A]

[written in other hand:  Actually, yeah, I wanna know too:  why are the classrooms in the Link always locked, even when the desk is staffed?  It’s not like there’s a surplus of rooms!]

The original question is far too general (I can’t comment on classrooms across campus), so I’ll address the Secret Scribbler’s follow up (specifically about the Link, the only location of classrooms in the Libraries). I was told that classrooms in the Link are locked when the Paul B. Williams Service Desk is unstaffed because people had repeatedly disabled the smoke detectors in some of the rooms so they could smoke. As is so often the case, a few selfish people ruin things for everyone else.