This is step one to implementing true deletion of users from the database: add a new required function to activity modules.

Moodle decision not to truly delete users is correct one. We don't want any user-relating activities dangling without having an owner.

However, as time progresses, our user tables (at least those not using external authentication methods like extDB or LDAP), keep swelling. It is my observation that after a few semesters, as the courses are being recycled for new students (admittedly not all sites do that), data for many inactive/deleted students is removed from Moodle. THat means we have a number of users in the database who have no data related to them and could be cleanly and safely removed.

The problem is to identify those users. This has to be done individually by each activity module since only they know how their data is related to specific users. Hence, I suggest to required all modules to add a function which reports whether a given user has any data for a specific activity. I don't mean a specific instance of an activity in a specificcourse but any instance of a given activity in any course.

This function can be then used for user overview and for checking whether a given user has any data.