Speaking as a sometime educator and parent...the HELL?
If I were still in academia I think that I would have just been strongly tempted to cross Carnegie Mellon University (a very highly regarded research university in my research areas) off my list of places to consider working at. I have kids, and I want them to get good educations, if possible at public schools. (If you want to tell me it ain't possible, you've come to the wrong store, considering the HS that I attended
To those that might think that this is a good idea, I will say this:
You can argue that percentages or letter grades are an unfortunately 1-dimensional view of performance, and I'll agree with you wholeheartedly.
You can argue that teachers should be given some latitude to give a letter grade that is not directly in line with a specified range of percentages, and I'll concur that this is reasonable in principle (although there should be checks for abuse, i.e., required justification in writing for exceptions).
You can even argue that teachers should have the latitude to entirely ignore one or two assignment or quiz grades in determining a quarter/trimester percentage or letter grade; I've seen that work OK (with the above caveats).
But if your argument (as chronicled in that article) is essentially that one 20% (or, worse, 0%) can torpedo a kid's entire grade...my answer is that in the small, it should not be able to do so: there should be evaluations (tests, quizzes, homework) on a frequent enough basis that one bomb shouldn't cause you to flunk if your other grades are decent. In the large...if you've got 20% on _all_ of the assignments for the quarter, then, yes, you're going to have to hop to it in order to pass for the semester. This is as it should be.If we believe that percentage grades are a metric that we want to use at all, we should not be compromising their validity in such a fundamental way.
(And to the chairwarmer in that article who asserted that they were worried about a sense of helplessness leading to behavior and attendance problems...what kind of behavior and attendance problems do you suppose that _this_ policy is going to entail? You've just told kids that if they skip half the assignments that they can still get a C. How do you suppose that will affect the students that put in the work every time to get those 75% scores?)
I remember my fifth-grade teacher pointing out that bombing (or skipping) a few assignments or tests, even if you ace the rest, can get you a worse grade than doing middling-to-good the whole time. I was pretty sure that she was talking (at least) about me, and I took it to heart. Kids can figure this out, folks, or at least recognize it if it's presented to them.