We recently discovered a hidden gem! When editing an activity we often overlook the "Permissions" link in the Administration block for the activity.
Within Permissions we discovered two things we can do: Prohibit viewing based on course role and control permissions to stop teachers from editing (Accidently deleting) an item from the course that is important or required by an institution.
This is extremely useful if you provide course templates and you have teacher instructions as a Page Resource and do not want students to view it and do not want teachers to delete it. Within the Permissions of the Page activity you can prohibit students and below from viewing. Then if you modify permissions for the teacher role within the activity you can remove their ability to Manage it, thus removing the delete option.