There is also "live and let live" by which, if someone isn't doing just what you want, you don't get on their case. There is also the common sense realization that if an experienced user is breaking a policy, essentially making a newbie mistake, that they may not be aware of it and may be somewhat embarrassed if attention is drawn to it in an aggressive way.
Of course. Basically, you must ask yourself: "Will fixing the problem do more harm than the problem itself causes?" If the answer is "yes", then "live and let live" is the best response.