well gee, that's a great idea. it's not like students could do anything to screw each other over, especially if they had a grudge!!!
Students who incorrectly grade get points taken off of their own score.
how do they enforce that?
What do you mean?Grader writes their name on the paper in red pen, if the graded student finds they were marked incorrectly the grader gets in troubleIt's not hard to understand.
Sometimes we wait up to a month for scores otherwise. Sometimes they'll wait until near the end of the grading period to punch everything in.