your question is counter intuitive to your claim of less government...I am normally pretty supportive of less government control and intervention unless necessary. I don't think smoking should be outlawed or anything, my only problem comes when it affects others besides the smoker. People are free to do what they will with their own bodies, but not necessarily free to do what they will with others. That being said...
Most of us should be able to agree that when a child is being beaten and bruised by the parents, even though the bruises go away quickly and it's temporary, it's still child abuse. But what about the damage done to a child by secondhand smoke? That damage can last many years and in some cases, can be fatal.
Should we treat smoking around your child as another form of abuse?