Participants of the STARS Integrated Moodle service are always in sync with the class rosters on the STARS database.
Each night, a program runs and syncs the students registered / enrolled to a course. If, for example, if a student drops or withdraws a course, the change will be reflected to the Moodle database during the next run of the sync script. There are some exceptions to this, like some guest users who are not mentioned in the STARS database.