how do you intimate that something is "bad" to your child if they see you doing it.
do as i say, not as i do?
i've yet to see that work. it undermines ALL credibility on the parents part.
children often DO learn what not to do by counterexample (example - you see your parent die of cancer caused by smoking. that's pretty good incentive not to smoke), but this (imho) puts the onus on the child to learn what they haven't really been taught (per se)