Meanwhile, back in the real world.....usually we only enforce this rule for persistant offenders!
I am sure this is what happens normally.
However there is the other side of the argument, and that is the occassional (sometimes more than occassional) case where the instructor or the school insists on flying despite the conditions being too poor to enable the very low hour student (fighting with the controls) to learn anything. I had quite a few lessons like that. It's debatable both ways whether this represents value for money to the student.