Say a 17-year-old Czech student goes to a club with a bunch of his friends one Friday night. Though the drinking age is 18 here, the student walks in, makes a comment to the bouncer, the two share a smile and he and his buddies are in.
Now imagine this with a 17-year-old American testing his luck at a bar in the heart of New York. The bouncer takes one look, spots the fake ID, rips it in half and hands it back. So it will go for the next four years.