I'm cross posting here from the OneNote space to give my idea more visibility.
My suggestion is that OneNote Class Notebook Welcome section, technically the main section, should be personal. It then eliminates the need for a separate Teacher Only section and makes more logical sense.
A teacher would normally assume that this part of the notebook is meant for teachers’ personal use – only to find that this is shared across all student’s notebooks (for viewing). The Welcome section is currently an unnecessary duplication – since Class Notebook-wide sharing happens in the Library section.
The same applies to the students’ Notebook. When they open the notebook, they should already be in their main section, eliminating the need for a separate personal students’ section group. I.e. The welcome pages would be in their main section with Assignments, Notes sections etc. all on the same level. Again, I think this makes much more logical sense. To clarify - the student's personal section would be what the teacher accesses when he opens the student's notebook.