I have evidence in form of drinking classmates. Moderately so in my school because it was cultured, but classmates told it was much worse in their previous schools. I guess it largely comes from the families.
Even that isn't particularly popular amongst children. Youth drinking has dropped substantially over the years.
I also don't really get your point. We should stop under 18s/16s from drinking via asking their parents for some by... removing all restrictions altogether?
You imposed yourself into a debate where someone said restrictions have zero effect other than creating black markets. I and others pointed out that's untrue.
Then you came along and now you seem to be arguing with me then now you're agreeing with me but being really vague about it.