<p>What they should do for students repeating courses is that anyone taking a course the second (or third, etc.) time should only be allowed to register for the waiting list, ordered by the number of times the course was previously taken (more tries getting worse priority), with ties broken in favor of those repeating D/F grades over those who withdrew late* or are trying to repeat passing grades.</p>
<ul>
<li>Withdrawing late means after the deadline for some other student to add the course and take the place of the withdrawing student.</li>
</ul>