Ho ho ho. Love that line. "Their inner Alfie Kohn".
Some of my colleagues closed their gradebooks two weeks before the end of the school year and dumped the last two week's assigned student work in the trash. Shouldn't this prompt doubts about the enterprise? Like much assigned classwork throughout the year, the last week's work was for show. I believe that teachers often assign classwork and homework with no larger instructional purpose than to keep students occupied or to prove to parents or supervisors that they (teachers) are doing their jobs.
As a rule of thumb, if you have to lie, you're doing something wrong.
Early in my career, I assigned enough classwork to keep students busy. I assigned homework. The problem was, grading enough work to occupy students' time in class kept me busy for hours after class (and I was a Math teacher. For English or History, it's worse). Grading assigned homework involved another problem: who's work was I grading, anyway? What can a grade mean if I don't know where the student got the answer?
So I stopped. We practiced on worksheets of my own composition (teachers routinely violate copyright). I graded a short test once a week, but not classwork, and a quarter final each quarter. The only homework that mattered was a file of all collected classwork and tests, which counted 1/2 of a grade point (i.e., C+ => B).
Really, now. If you lift weights for an hour a day five times per week, you'll bulk up. If you trot around the track for an hour a day five times a week, you'll get fit. Use class time honestly and you'll find you use it well. You'll save the students' time and your own.