GP was describing the platonic ideal of why we have universities instead of just textbooks, so I'd venture a guess that you're the one with a biased perspective here. Sure, some students cheat, and the appropriate penalty is throwing them out of the program. But pursuing that end to the point that you forbid students from engaging in normal collaborative learning is nuts.

As you point out, there are plenty of students who flat-out copy each other. Filtering out those students does plenty to enrich the remaining students, you don't need to go on witch hunts to find ever-more subtle cheating.