The place this can make a difference is in the quiz reports: steps to reproduce:

1. Go to the quiz report for a quiz (e.g. https://qa.moodledemo.net/mod/quiz/report.php?id=30&mode=overview)
2. Note that some students are shown
3. In another tab, open the Permissions setting for that quiz (e.g. https://qa.moodledemo.net/admin/roles/permissions.php?contextid=9063)
4. Remove one of the mod/quiz:reviewmyattempts or mod/quiz:attempt capabilities, but not both.
5. Reload the quiz report.

Expected result: the students are not shown.
Actual result: 'No students enrolled in this course yet' message.

Original report came from this thread: https://moodle.org/mod/forum/discuss.php?d=400078#p1615266