I was a full-time student for about 20 years, all said. I was never assigned a homework assignment that did not benefit me in some way. Whether by teaching me something new, honing a skill, or reinforcing and deepening knowledge I already had, each homework assignment I did was helpful. It seems like the author wants to cut out all of this beneficial work just because he can do well on tests. I don't think that's a good idea.
Your null hypothesis (or whatever it's called) is very pessimistic. Even if you benefited from those assignments, you might have benefited more from doing something else instead. Shouldn't it be your choice, as long as you can demonstrate command of the material?
My assumption is that the teacher should optimize the class on the amount of the course material the students learn, and how well they retain that knowledge. As far as I can tell, the goal of all of the teachers I know is to get the students to learn the material the best they can, so they structure the class around that ideal. I fully understand that some students just want the credit, or to just get by with whatever they deem to be sufficient knowledge, but I don't think it would be generally beneficial to structure the class to give them incentives to do so.
In that case it would be a pre-testing strategy, not a post-testing strategy.
If you have these pre-tests, you can then put more people in the right classes anyway, which would allow them to use their time well. you could then do something else which benifits you more, like a higher level, or faster class.
