A Mercy Moment is a pass that allows your students to turn in one assignment one day late with no penalty or explanation. I replaced my homework pass (which enabled a student to "get out of" completing an assignment) with this option, which still requires completion, but gives student the opportunity to extend a deadline for whatever reason. There are some assignments (projects, journals, timed assignments, etc) that are not eligible for the Mercy Moment; I announce that or put in writing when assignments are made.
I also allow students to turn in unused Mercy Moments at the end of the semester for added points on a low test grade.
Students love these passes! I love the fact that they offer flexibility, yet provide accountability.