UPDATE: Work has started on this idea. See http://confluence.sakaiproject.org/display/CR/Home for details.
Like in other LMSs, Sakai should support conditional release of elements.
Prof. Martin requires his students to read his syllabus and get at least 90% on a quiz he has prepared to assess what their students understand of it. Students are allowed to retake the quiz as many times as needed to get the required passing grade.
Diego (a student in Prof. Martin's course) doesn't see anything in his course site but a link to the syllabus, and a link to a Quiz called "You must pass this quiz before accessing course material for week 2". Diego looks at the site files in the Resources tool, thinking he could bypass this requirement, but still doesn't see anything but the PDF syllabus file.
Diego reads the syllabus and attempts the quiz for a first time. He gets 80%. Nothing happens, he has to do it again.
Diego passes the quiz on his second attempt, and a new link appears in his menubar, linking to all class material for the next week, including resources and learning activities.
Could we have some sort of "cascading permission scheme" to deal with permissions?
Children permissions could override parent permissions.