I was disappointed to find that users had discovered multiple workarounds to access rosters prematurely via Course Mastery tab, launching the gradebook, or seating charts. Instead one has to manually toggle tasks under the selected user type: "My Gradebooks," "Manage Grade Books," "Copy Grade Book," "Gradebook SPA," "View Grade Book," and "Manage Academic Class Seating Chart" to completely restrict access to class section rosters. Turning something off in group page access should turn it off, completely. Respectfully.