This is exactly right. People who get away with some rule-breaking, whether it's large or small, once will start to think maybe they can get away with it a second time. Get away with it a dozen times and you start to think you can get away with it every time, leading to the "people who genuinely don't think about the consequences when they are acting" that cortesoft mentioned. That sort of behavior isn't just a facet of personality, it's trained (or it might be more accurate to say, it wasn't trained out of them — all children act on impulse, it's the nature of children, but if their parents consistently punish them for sneaking cookies out of the cookie jar and they never get away with it, they eventually learn not to do it in the first place and to think about the consequences before they act).

So when a lot of people grow up in an environment where small rulebreakings are consistently caught and punished (the former is more important, can't punish what isn't detected), they learn from an early age that rulebreaking carries consequences nearly every time, and you end up with far fewer people willing to break the rules.