> Similarly, one of your nephews has a friend with parents that don’t lock their liquor cabinet, which means despite all the laws not allowing sales of alcohol to minors, they still have access to it.

Funnily enough that's how I ended up getting drunk the first time, a friend stole some liquor from their parent's liquor cabinet :p We both ended up in a lot of trouble over it, him more than me obviously.

But that's sort of the point as well, if they go down that route then it's easier to catch them and it's easier to punish them for their actions. It's also much more obvious that what they're doing is the wrong thing because it involves a lot of sneaking around, deception and even stealing from your own parents. It makes kids less willing to do it in the first place (unless you're a dumbass like my friend and I).

With something like a smartphone, your parents might not let you have one but every single other kid around you has one, so at that point it only becomes an arbitrary rule that your parents imposed on you, and not a wider rule that everyone has to adhere to. If we treated smartphones for children similarly to how we treat alcohol or tobacco, the parents would have a much easier time enforcing these rules.

> ...they’re now going to be inherently biased a certain way

Or they could go the complete opposite way as well. I mean it's the most common trope/facet of being a kid, that stage of rebellion against your parents and their rules. You still have that with things like alcohol and tobacco of course, but at that point it becomes rebellion against society et al which is a bigger deal and harder hurdle to get over than rebelling against your parents and their rules.