Does the minimum age of 21 to buy alcohol have any real effect in the US? I seem to recall reading, that the overall average consumption in units per head of population is greater than the UK and several other nations. Some states are 'dry ' as well, and in others, like Pennsylvania, I think alcohol is not generally available in food stores (bit like UK, 1970's??).
Who's going to stop the hordes of Scottish clansmen descending on us now? I can just see them girding up their kilts as I write. Our off licences had better get stocked up on all the different brands of Scotch.
When I have been in the USA you always need to show ID when purchasing spirits, and it seems to work OK in the areas I have been - pretty limited to Orlando though.
I also think it is a cultural thing we have to try and change by Education. We cannot say to people, OK you are 16, you can get married, have children, work, pay tax, fight in the armed forces but we do not trust you to manage your alcohol intake. There must be another way?