It takes discipline to know what to do and not as parent, it is also not proper to use our own foolishness and upbringings affect the destiny of our children, smoking in from of them in indirectly telling them to also be learning how to smoke, which is very bad as parent to do, there are many things we are supposed to do in helping our children as they are growing and not to be disgracing ourself around them by our behaviors.
Some parents are just anyhow people, they real don't care about the future of their children, they do a lot of things in front of their kids, not just smoking, they fight each, exchange words in front of their kids, without minding the affect on this kids when they grow up.
Smoking or any indicent act should be done in absence of your kids, because children learn from what they see and they try to repeat it. I saw on the Internet a girl child using her mum's vibrator to touch her self, where on earth did she learn that from, it obvious the mum used it in her front and she try to repeat it. If to care about your children, they're thin you don't do in their front.