I suggested no solutionsI did put words in your mouth but the implication of your original comment, that smoking around children be banned in the home, was that there would need to be some sort of policing of this activity. To police an activity in an individuals home we need to impinge on some pretty important freedoms. So we have a choice - a severe nanny state where we address shitty behavior on a case-by-case basis or teach people to be more thoughtful so that we can prevent shitty behavior from the outset.
PS: We used to think beating children was ok so times change even if few people in up in prison.
Sending a parent to jail for beating their child is wise because beating a child imperils the child's life. On the other hand, sending someone's parents to jail for smoking around them will be more damaging than exposure to cigarette smoke. The medicine is worse than the disease. What's more, you assume all people are rational actors which we know is fantasy - just because some people have gone to prison in the past for some random transgression won't be enough to stop another person from doing the same.
Even though this unfortunately isn't the case, jail should only be used to separate violent people from the general population - there are far better methods for dealing with non-violent offenders, chiefly community service or a fine.