Here's a story...
So a student registers for a fall term course back in '04. As a result of not paying the course fees, he gets de-registered from the class automatically.
Later in the term, he appeals to get re-registered back into the course. They put him back in and fees are added back to his student account. Fall term ends, exam period comes and goes, still no payment for the course. Final mark in said course: F
So now it's fall term '05, said student has the same fees outstanding on his account for the fall term '04 course. Guess what - now he's appealing for a back-dated withdrawal to get him out of the course and therefore removing the fees owed. He swears he doesn't remember appealing for the re-register back in late fall term '04.
Part of the appeal process requires a reason for the back-dated withdrawal. Usually a doctor's note or something similar. Our student in question presents a doctor's note with - wait for it - Bipolar Disorder.
That's right. So no wonder he keeps jumping in and out of the course. Half of him wants to take it; the other half doesn't.