It's always fun to catch out the big wheels in Hollywood! Recently we saw Saving Mr. Banks, which is an excellent film by the way. In it Mrs. Travers, an extemely uptight upper class Englishwoman arrives in Hollywood. Throughout the film she requests tea and always insists that the milk be put in first. Now it happens that Mrs. Travers was neither English nor upperclass - she was raised in poverty in the outback of Australia. She also was never married.
The source of U and Non U was Nancy Mitford, who became an authority on the entire class business.