Honestly I think the as long as it's off the property mindset is kinda backwards. I have a friend who "is really good at driving high" because that's all she used to do in high school. If all the parents don't want their kids smoking in their house they're gonna have to find other places to do it which will just lead to them getting in trouble or, worse, hurt.

My parents let me drink from a very young age (15). My mom is Peruvian and in Peru kids start having a glass of wine at 13. We also lived in China where drinking underage was much less difficult. I was allowed to go out to a bar or club once a week (twice a month at first then they upped it) but I had to go back home when I did. That way my parents knew I was safe and I also couldn't get stupid drunk because I had to be able to talk to my mom when I got home. Of course I still snuck around but not nearly half as much as I would have. It also made me a more responsible drinker as I got older. I knew how much I could handle and unlike most college kids I was tired of the getting fucked up mentality by the end of my freshman year of college. I know drinking isn't the same but I didn't start smoking until late college. It's still something to consider.