If the students consider this material useful to study, it's unethical for a professor to deny them access to it. Making the knowledge harder to acquire is prec

If the students consider this material useful to study, it's unethical for a professor to deny them access to it. Making the knowledge harder to acquire is precisely the opposite of his job. Especially when the only reason is that the professor wants to be excused from doing the other part of his job by simply recycling an old test.