It is difficult when allowing make up exams because you cannot hand back the ones already graded and that is not fair to the other students. I have figured that letting the students see their exams and requesting them back because the class still have a few people who need to take the exam works best.
However, when the makeup tie is then extended and extended, you want to be fair to all of your students but at some point the extenstions have to stop. How do you develop a clear cut this is all that will be allowed for makeups? There is always extenuating circumstances but there has to be a limit, right?