It's a funny twist of history that Karl Marx' "dictatorship of the proletariate" and the "classless society" are so profoundly expressed in US American dresscodes and have become one of the country's best cultural export articles.
From Levi's via Nike to Ed Hardy ...

Unaesthetically dressed guests should be thrown out of any first class or real luxury hotel ...

Every stupid discotheque does it, but airlines and hotels didn't have the guts to enforce dresscodes. I am sure it was a mistake in the long term.