I wonder if it also has to do with the possibility that the students would just go to the library, and not go to class at all; that there isn't any kind of "pun

I wonder if it also has to do with the possibility that the students would just go to the library, and not go to class at all; that there isn't any kind of "punishment" for doing that instead of learning? By "punishment" I mean everything from truancy enforcement to "societal disapproval"; it may be that in some cultures this isn't looked down upon? That's all just a WAG, though...