Are there any exceptions to the law that prohibits the sale of alcohol to minors?

Wouldn’t it be the incorporated store itself making the purchase?

In order to get a liquor license here, either on or off sale, you have to provide evidence that there is at least one manager that is the legal drinking age. The distributor can sell alcohol to the licensee, not the clerk or anyone else. Depending on the town or county laws, a minor may or may not be allowed to accept delivery or sell the product.

In the UK, you can legally consume alcohol (beer, cider or wine, not spirits) in a pub, at age 16 or over if you purchase a ‘table meal’ at the same time and are accompanied by an adult.

As far as I know the answer is no to both questions. (USA)

No, no exceptions.

Not in Germany.