I always say that if you can't be a good example then you might as well serve as a horrible warning! (btw, I am in the horrible warning category, never was much of a good example)
This reminds me of a an old friend that had lost a leg to cancer and was on crutches. We ran into him at the videostore and my then 3 year old says (they ALWAYS do this to you) "What happened to your leg?". He was so good about it and said without missing a beat: "I didnt' listen to my mom and dad and it fell off". She was good as gold for a LONG time after that.