I've been to college and suffered the frustration of trying to juggle classes that take place at inconvenient times relative to each other. But we don't seem to have the conflicts divulged to the students. Hermione "just signs up for everything", she doesn't say "gosh, it looks like this class and that one conflict, so I'll have to pick one - but I can't choose! Aaah! - Professor McGonagall, isn't there something you could do?!"