From a development point of view however, the due date is the original setting and allows the tutor to determine whether submissions can be made late - they are marked as late, so it is easy to see those that were submitted on time or after the deadline, while most institutions would have a system of 'extenuating circumstances' whereby a late submission may be allowed.
It would be interesting perhaps to find out what the majority use case is in terms of defaulting late submissions to be allowed or not, but for me I think the way it is set up at the moment is certainly perfectly in line with what my institution does and my awareness of what other institutions do. Without that late submission (or if it defaulted to not allowing them and relied on tutors remembering to turn it on) we would have to set up a different way of getting late submissions in and returning feedback and grades for them.
