I was one of those students (great course!) and you're right. So, folk sign up on the spur of the moment and then drop out! Big deal. Where’s the dirty secret? Was there any cost to signing up on the part of the student or the instructors? Not at all. Why then probe further into what would be a vast range of personal reasons for not completing the course?

We have to ask ‘Why do people make cost-free momentary decisions and then fail to act on them?’. Do we think this an important question? I suggest most of us have much better things to do with our time than agonize over this.