Why and when does IS cancel reservation of students from examination dates?

IS automatically cancels reservation of students from examination dates if it detects that:

the student has already gained a passing grade in the course evaluation,
the student is no longer enrolled in the course,
the student has exhausted the number of re-sits for the course,
the student is not entitled to a second re-sit because he/she is repeating the course.

The automatic cancelation of reservation usually takes place at night when IS checks applications for future examination dates.