I went to a school in the South which has an honor code. No lying, cheating or stealing. It's an honor code violation not to turn in anyone committing an honor violation. The single sanction is discharge from school.
I am against honor codes. They institute great uncertainty into the mores of practical folks, and institute a reign of terror, in my estimation, because they set the bar at the personal standard of the most stringent interpretation of "honor" by its most zealous advocate. Lost in this is the notion of "prosecutorial discretion."
In the realm of ordinary affairs, offenses pass a number of preliminary barriers before they appear before the ultimate arbiter, a court of law, where they become fully vetted. First, though, a policeman, or injured consumer, decide if the "offense" (jaywalking, or a dinged car door) is worth pursuing. Only then is it passed up the food chain. We all have a sliding scale of values for this--a tiny pock on the bumper earns the culprit a glare, a dent in the quarter panel elicits an exchange of insurance information (the "referral"). But no one lives in fear that their de minimis standard in ignoring a "violation" will earn them a trip before the tribunal and ultimate ejection from the system.
In honor code environments, cheaters go on cheating but take greater care not to get caught. They can actually thrive in the atmosphere of elevated, but not necessarily warrantedly so, sense of trust. Practical folks maintain a low level of anxiety that their common sense attitudes in how they go about their business, either through omissions or commissions, could come to the attention of zealots with stringent, rigid or tortured idealism, who would feel duty-bound to turn them in to the honor board for potential application of the ultimate (and only) sanction.