Yeah I'd say it works. I've seen many minors doomscrolling on their phones. I haven't seen any with a beer in hand. That's not to say there aren't any, but there are fewer.

It is my impression that when drinking age restrictions are introduced, drinking among the (now) underage population goes down. Not disappear, but goes down.

My personal experience is also that 17 year olds in countries where the legal drinking age is 16 drink more than 17 year olds where the drinking age is 18, but I don't have numbers on it.

It doesn't need to be 100% effective in order to work.

Do minors drink less than they would if we allowed (or even encouraged) them to drink or use drugs?