What do grades mean?

I am the principal in a grades 7-8 school, perhaps the last venue where we try to give kids second, and sometimes third, chances. This happens mostly with discipline, but also with academics, because this is the last time when a kid's grades do not really matter. What I mean by this is that I am unaware of any college or employer that has ever requested a transcript from a student's junior high school. (Ryan McLane at Education Week)