Homework is necessary.
From what we know about the human learning process, we know that real learning cannot happen unless students are actively engaged with the material to be learned in several settings. Cadets don't know that homework is necessary. The learner will not appreciate the need for preparation unless the learning experience is structured to make that need essential. This is the role of the teacher. The way one structures the learning situation depends on the level of the student and the nature of the course material.