Good to see we are top of the league at something.
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Seriously though it depends - are these underage drinkers taking a a quick swig just out of curiosity or are they drinking with their parents with food? Is it just very small amounts? I recall when I was very young trying my parent's brandy, which they got for guests. And was put off for life. I started drinking in pubs from 16 - the days when smoking was still allowed and you had old beefy landlords, who knew who to serve and how much. where you'd go to your local corner shop and they would serve you without asking for ID.