Talk:Class 3-3/@comment-68.103.207.111-20190609200801/@comment-30834068-20190609215836

Chibiki remarked that the charm doesn't always work, and sometimes they can't figure out why it failed.

A hypothesis of this time is that the extra was a teacher, not an unknown student, so designating a student to be non-existant for the year wouldn't have counteracted the extra 'student'.