Looking at three diff threads on this story, people are assuming a bunch of things to be known that cannot be known from this video, such as:

* assuming the test bank is publicly accessible or is supposed to be (the instructor's statement that the publisher has been informed that the test bank is compromised implies it is intended to be private to instructors);

* assuming the test bank is accessible through teacher's versions of textbooks (it could be online via authentication);

* assuming the access by any student must have been illegitimate (the students could have easily thought it a study guide, and the source could have been someone other than a student--some instructors also can and do reuse questions and reward students for researching and studying them);

* assuming the access must have been legitimate;

* assuming the staff can prove particular students cheated (yeah.. we just don't know this, especially if we don't know how the test is structured or how the data analysis works);

* assuming the staff CAN'T prove particular students cheated (first, you can't assume something impossible just because you can't imagine how it could be possible; second, data analysis is shocking in what it can inform; third, the data analysis can be used just to indicate suspicious tests that the human instructor and TAs then review themselves; (and fourth, yes I did just nest semicolons and parens within other parens and semicolons));

* assuming the student who turned in the copy of the test bank was one of the cheaters or could even make use of it (it's possible they acquired it afterwards and turned it in out of spite or after discovering how widespread it was and that it would greatly disaffect the class results);

* assuming students feeling guilt implies guilt of the actual wrongdoing (people can feel bad about actions that aren't wrong, even when they know they aren't wrong);

* [I can't even list all the rest of the ones I've read..]

Then there are the assumptions that, even if true, aren't relevant, like:

* assuming students paid money for it because it's a business school
* assuming older generations have superior ethics to the current generation (many would argue on the hypocrisy of older generations accusing others of entitlement);
* whether the instructor is lazy or not (this is only relevant to issues of perceived value of the class, instructor, program, and school; not to the issue of academic dishonesty)

I have read these and many more from both people criticizing the students and people criticizing the instructor. The point is that people in these threads are assuming the video gives more facts than it does.

The only relevant factors I see are how they acquired the test bank and how the instructor communicated the nature of the exam. Neither of these factors are actually that easy to determine from the video. On one hand, the very existence of the test bank isn't something the instructor should feel either has to be divulged, if he has a reasonable expectation that it is supposed to stay private, or explicitly informed to the students that it's off limits. On the other, this is also a possible scenario: that some students reasonably assumed past or public exam material was fair game; encountered the test bank publicly (or acquired it from someone else thinking that they got it legitimately); used it to study; thought, upon seeing the exam contained some of the same questions, that they had studied from the right material; and only realized it afterwards, even as late as when the instructor revealed the extent of the incident, then felt compelled to confess. Is it likely it happened with all the confessors? Probably not. Is it possible and plausible it may have happened with some of them? Certainly. Presumably, all the confessions were in private, some possibly anonymous.