Unfortunately many teachers don't post notes, they expect you to transcribe what they're saying. So inevitably, no one is actually listening, students just wind up comparing and trading notes, trying to 'study' from there, and seeing where it lines up with the textbook.

I agree, the classes where I've learnt the most are the ones where notes are posted ahead of time, you can look over them, actually listen during class, and gain an understanding of the subject, not just memorize bits and pieces to then transcribe on the exam.