This makes me feel a little bit better about the students who just disappear when I give them a chance to rewrite an unsatisfactory paper (but not a plagiarized one. Those, at least if the plagiarism is deliberate -- e.g. all from one source -- go straight to the honor council).
That's when a face palm needs to be applied to the back of their heads. SO frustrating.
I feel bad because I created this half credit policy because so many students failed my chemistry lab. Now I have a bunch of students turning in rewritten reports that my grad students have to grade again. Still, the students waste everybody's time by plagiarizing.