Sometimes a student may need to join a class midway through the year after several assignments or marking periods have already passed. In these circumstances, it would be nice if the student didn't have these previous assignments assigned to them automatically as it makes it look like they're missing work. Ideally, the teacher should be able to decide which of the historical assignments they should or should not have assigned to them.
A student (and their parents) who was not enrolled in the first term of a class, should not need to see endless "missing assignment" notices for assignments that they were never expected to be assigned or complete.
We are a rolling admissions school, so this is a constant issue for us as we enroll new students throughout the school year.