As a CS professor with a lot of concern about cheating in general, one sentence stood out to me:
> One of the offenders was actually a repeat offender from the prior assignment and was also dismissed from the class.
This tells me that this professor who posted the blog entry may not quite understand the problem.
Ethics aside, students cheat because they believe that there is a positive utility in doing so. That is, they believe the expected likelihood of cheating is better than the expected likelihood of turning in their assignment cheat-free, even for a zero. Ultimately the only way to curb cheating is to make the utility negative. And not only negative: it has to be so obviously and publicly negative that it shatters the students' own rosy visions of cheating and getting away with it.
So what did he do wrong here? He allowed a student to cheat not once but twice, and then the only punishment was to fail him. Let us presume that turning in a zero twice, plus average work for the rest, will land you an F. If there is even an infinitesimal chance of cheating and getting away with it, this tells a desperate student that the net utility of cheating on two assignments is positive. If you need three zeros to land an F, you still only need a small probability of getting away with it. And so on.
Basically he slapped the students on the hands. He's part of the problem.
My recommendation to his institution would be as follows: a minor offense (as ultimately decided by an Honor Court, not the faculty member) would be course failure. A major first offense would be course failure plus community service. A second offense would be dismissal from the University with no readmission. And whenever a student is failed or dismissed, the department lets their students know that such an event occurred (with no details). Students should be made aware of how often they get caught as a group.
Then there was this sentence:
> Students would come to my office and deny everything.
It sounds to me that he was handling cheating on his own. This has two very high negatives. First, it sucked up enormous time on his part when there's a perfectly good institutional mechanism (the Honor Court or whatnot). Second, punishing such cases on his own opens him up to direct liability. Faculty can and are sued by students for doing such things. One of the purposes of an honor court is to have his institution take the liability since they made the decision. He should have simply written the students up, submitted to the honor court, and wiped his hands clean.