My dad was a smoker when I was growing up and often smoked in the car, especially on long trips to my grandparents'. He always cracked the window, but then I was in the back seat freezing while he finished his smoke. He's since quit smoking, and there is much more education about second hand smoke than there was 15 years ago. I don't know that he'd be doing the same stuff he was a smoker with a young child now (I know I can't imagine him smoking with my niece in the car).
I have no problem with this law. I don't know that it will do much as a law, but there is a lot of publicity/promotion going along with it ("Campaign for a Smoke-Free Ride), which I think may make some people stop and think. For others, it won't matter, and hopefully sooner or later, they get a fine.
Really, I think it should be illegal to smoke even in the same room as a child. It seems like it would be common sense, but there are A LOT of people who do not have common sense. A couple years ago, I was at my parents' friends' place and their daughter was drinking a cooler, then breastfed her 3 month old son, and then held him while she smoked her cigerette.
The difference between legislating something like smoking and legislating poor eating habits is that smoking DIRECTLY effects the children around you....they are forced to breathe in that air. Once that air is breathed in, there is no way to reverse the effect of that second-hand smoke on the person's lungs. Even if they get older and choose not to smoke, the effects of that second hand smoke will stay with them.
Unhealthy eating, on the other hand, mainly affects the health of the person doing the unhealthy eating. There's no "second hand fat." Now, I can't say I have the best eating habits, and I attribute to it PARTIALLY to the fact that my house growing up was full of junk food and my family ate large portions. I, however, think that effect is much more indirect than second hand smoke. Even if I picked up poor eating habits from my family and was a little overweight as a child, I have received education since Kindergarten about healthy eating. I can make good eating choices or exercise to lose weight or become a healthier person in general. However, that second hand smoke from when I was a kid in the car? It will still be there.
So, I do know that it is a slippery slop, but I think it was a decent decision on the government's part. It may seem like they are getting too far involved in peoples' personal habits, but I'm all for that when it comes to protecting children who are not yet able to protect themselves. As a teacher, I know all to well, that there are parents out there who do not do that on their own, without the government getting involved. And there's just not enough CAS workers out there to reach every child who has a slightly moronic, but not completely unfit parents.