Ah, yes, the Land Of The Free<tm>...
...where "your papers, please" applies to alcohol.
My brother-in-law, a native of Manchester, England (and well
over 21) came to the States to visit, back when he was still my sister's fiance. He, my sister, and I went across the street to our nearest bar, and ordered some beer.
Well, some time recently, the cops had sent an underage snitch into the bar, and he got served. So, now, the bartender was in full "papers, please" mode, and my future brother-in-law had left his passport at my sister's house in Michigan. Needless to say, we ended up having to go elsewhere.
Well, elsewhere was another pub in town - and they had just instituted a dress code - no tank tops. Guess what he was wearing?
We managed to smooth things out with the proprietor, though, as it was quite clear that we weren't up to trouble.
What a welcome to America! He did marry my sister, though, and they are living in Michigan... and I'm quite proud to call him my brother. Even better, he has a taste for good single malts!
 I rarely set foot in bars - I can't stand the cigarette smoke.