I am using Moodle in a self-serve, corporate training environment. As such, we don't really have "classes" that start and end on particular dates. Everyone signs up for a metacourse, which enrolls them in all of the courses, which are available to whoever wants to take them, whenever they want.
As a result of this, anyone who has ever signed up is perpetually treated as an active student in the course. This poses a problem because it means that if I add a gradeable activity (like a quiz) to a course, it immediately lowers all of the previous students grades.
What I want is some way for students to take a course, and then have Moodle know when they are done, and "freeze" their grade so that it isn't affected by subsequent changes to the course.
Is this possible?