Add option on Courses to forces activities to be completed in order (or permit removal of message about Restrictions on Activities).
Using the Restrict Access setting on each Activity within a course is tedious and clutters the screen with unwanted messages. (on course with 50 activities, I am required to edit each Restriction setting on each activity).
All Activities within the course should be shown, with only the first activity in the course accessible. Or if completed, the next activity should be accessible. (So at any point in time, only one activity in the course is accessible). Perhaps a message below the course is in order to indicate: "Activities must be completed in order."