Late books should not result in graduating a year late

Registering for classes is serious. If you don't get into the class you need, you may need to wait a year to take it again, meanwhile missing out on other classes that require the initial class as a prerequisite. This can postpone graduation, resulting in the loss of thousands of dollars.

In the real world, when people return books late to a public library, they do not get fired. They simply get a late fee.