I think all it teaches my DD is that it's Ok to turn in a piece of ****, and get an F. You can always re-do it. Or not. She couldn't care less about her grades. But other kids get very worked up about it, and eventually may stop trying. In Jr. High, they are not going to be able to re-do work or tests the way they do now (they also allow kids to re-take tests that they fail).
The teachers say "Oh, you got an F. No big deal. Re-do it if you want." So what does this really teach? I don't get it. Since some kids are really worried about the grades or doing the assignment as written, they either stress out about the assignment, or ask for help from the parent. In some cases, parents don't want to see F's. So they help. Parents are probably thinking their kid is about to get kicked out of the gifted program because they are doing so bad. So the teachers are perpetuating this weird situation.