Both teachers and students should treat assignment deadlines in Moodle with respect or mayhem may ensue!
The teachers on their part should make assignments available well in advance of the deadline and they should never set a deadline later than 23.55 hrs on any given day! Once a deadline has passed, teachers ought to comment on the work handed in (If you are not going to give feedback in Moodle, why use an assignment in the first place?!) and contact students or groups who have failed to hand in.
Students on their part should always use a safety margin when handing in work and not wait until the last day and the last minute. It is perfectly possible to hand in draft versions of a task and overwrite those with later versions, so that if unforeseen problems occur, such as network connection interruptions, the student will still have work handed in, while it remains possible to request an extension of the deadline to compensate for the network issue. Naturally, students should also check the feedback the teacher provides after the assignment deadline has passed.