Dr. S just graded his first batch of student papers. Per his department's and the university's policy, he requires all his students to sign that their work is honor-code-pledged: "I pledge on my word of honor that I have neither given nor received assistance on this assignment." They can and do expel students for violating the honor code - people leave their laptops laying around, for example, because it is an expelling offense to steal as well - and anyone who is caught plagiarizing gets the summary boot. Exams are not proctored, and if a student is travelling, they take the exam and an envelope, do it on their own, and seal the envelope.
As part of the faculty orientation, the student body president got up and explained that yes, the honor code is draconian, but the students overall like it, because they believe they're all getting a grade they earned, because nobody is cheating. (It is also an expellable offense to know someone else is cheating, and not report it.)
I have a theory that this works best at schools like this, where the reputation of the degree matters more to the students than the fact of the degree. And the town is so small and rural that outside influences (and/or theft) pretty much don't happen either.
It's also traditional to announce after the first exam, "Well, I see from these scores that the honor code is alive and well at Mountain University!"