How to deal with cheating when university policy is ineffective? I am co-teaching a relatively large class with two other colleagues in a big university. Each semester, most students are amazing, trustworthy, and well-behaved and it is a pleasure to work with my students. But there is a very small group of students each semester who cheat and I don't know how to deal with them. 

The university has a detailed, strict, and elaborate policy for dealing with cheating. We send students suspected of cheating to a special committee where they decide if the student actually did anything wrong. The committee demands a copious amount of evidence before it convicts any student, yet at the same time, the university policy is so restrictive that we cannot collect evidence. For example, we are not allowed to do anything that indicates or suggest a student may have cheated. We are not allowed to mark their papers, move them during exams, or even talk to them. This means that most students get away with cheating if they are sent to the committee. Students who have copied identical answers from a neighbor over and over in quizzes got away with it in the committee. This process is so pointless that the course coordinator does not report most of the cases to the committee anymore.

I don't mind that a few students get away with cheating but the universities' restrictive policy shuts all the doors to any further discussion with the students. I am not looking for ways to punish my students. I want them to understand why cheating is unfair to other students and, hence, unacceptable. I want them to understand integrity and honesty are far more valuable traits than getting good grades in college.

Any suggestion on how I can communicate these ideas and their importance to my students?



Edit:

I am sorry for not being clear. My question is not about how to prevent cheating.  It is bout how to have a conversation with cheaters.

We do what we can to prevent cheating. We randomly seat students, make two copies of the exams, assign a good portion the final grade to labs, and use various other techniques. This question is about reaching to the cheaters and having a discussion with them.
Since you speak of "a small group who cheat," it sounds like most of the students do understand the policies and importance of honesty.  That remaining small group who cheats?  Nothing that you do or say is going to convince them not to cheat.

Likewise, university policies often make it hard to actually punish cheaters, because they begin with the presumption of innocence, which is generally a good idea.

A better way to approach the problem is to adopt a "layered defense" strategy of a number of small actions that reduce the cost/benefit ratio available from cheating.  Some of the sorts of strategies that I have seen include:


Increasing the separation between desks
Randomized assigned seating, which is likely to break up cheating conspiracies
Printing less questions per page, with lots of white-space for working the problems, so that an answer will not be visible for as long a period of time
Problems that are based on "showing your work" rather than obtaining the right answer.
Problems with many possible solutions, that convert copying into plagiarism.
Putting more credit into projects and labs, rather than exams.


None of these alone will solve the problem, but the more of them you can enact, the harder it is for cheaters to prosper.  Some of them may even help the non-cheating students, by forcing them to engage more deeply with the material.  The balance, of course, is that it all takes time and effort from the instructors and TAs, so you need to make your own cost/benefit analysis as well.