some parts of gradebook dont use enrolment tables and they should

load_users() in grade/report/grader/lib.php uses role assignments but doesn't use the enrollment tables to determine who should be displayed on the grader report. See calculate_averages() in grade/report/user/lib.php committed as part of MDL-20617 for an example.

Grep the whole codebase looking for other instances of "gradebookroles" and update them all to use the enrollment tables in addition to the gradeable roles.