As the bumper sticker says "Stuff Happens"...or something like that. When a student is called to active duty because of a natural disaster, or the student delivers a baby in the middle of the course, it is fair to give more time.
Since I cannot discern the truth of a student's situation, and the exemption from the "late penalty" should not be awarded on the basis of "the best alibi", I allow students to post late for full credit.
So, for fairness and student retention, I do not penalize for "late".