During my six years of teaching I have saved some material so I can reuse it from class to class. I recently took a class and found out that the instructor did the same thing except she didn't bother to read what she was posting and some of the information did not apply to us. It was very irritated so we would email her to ask for clarification and then she would send an email to all the students letting us know about the correction.
I think saving canned material is a good idea but instructors still need to read that material before posting.
