Fix #2:
I understand the point the author was trying to make about zeros not being a true reflection of what was learned or achieved, but where does responsibility fit?  I understand that there can be other "punishments" besides hurting the grade, but if those other punishments aren't met, then what? 
I'm thinking from a parent's point of view...If my son had all the time in the world to do as assignment, you'd better believe he'll use it.  He will be overwhelmed by the end of the quarter with all these assignments that he can still hand in because he knows they will still be accepted.

Fix #4:
As an English teacher who tries to "scare" the students into thinking they will be kicked out of college for plagiarism, I wonder how else to punish kids who cheat.  They make reference to the "real world" in the book, and how you get second chances to fix your "sin."  Is that really how it is?  There are punishments in the real world for copyright infringement and things like that, so what punishment fits the crime of cheating, I don't know.