by ben reynolds.
The lock is done via the gradebook, right? So, lock basically says, retain the state of this grade, which means it isn't going to signal a human to do anything, like give a grade.
I find the lock annoying. We aren't big graders in my part of this outfit, but at least one of my people did a quick grade in an assignment on all the students when half the students hadn't submitted anything. This locked the grades for all and prevented further submissions.