In the final scene of the movie Billie and Paul are pulled over by a motorcycle cop. There are three shots, one of them driving to the curb, one of them talking to the officer, and then driving away. The officer who talks to them is obviously much older (and bigger) than the thin young man in the first and third shots.
After Mr. and Mrs. Hedges leave, Billie goes out of the room dancing to the sound of the radio, with a lit cigarette in her left hand. The next shot shows her entering in the other room with no cigarette at all.
When Billie leaves, Harry sweeps the books off the desk where she has signed the papers. But the next time he comes into the room there are stacks of books there again.
In the first discussion between Paul and Billie, the position of Billie's left arm changes between shots.
In the beginning of the film, Billie puts her fur coats, one by one, on the porter's right arm. In the next shot, when Eddie puts the last one, all the fur coats are on the porter's left arm.
While visiting the Library of Congress in Washington, DC, Paul Verral explains to Billie Dawn that the country's whole government is based on "these three pieces of paper." In reality, the Declaration of Independence, the Constitution, and the Bill of Rights were written on vellum, or parchment, which is made of stretched and treated animal skin.
No attempt was made to recreate the interiors of the Hotel Statler where Harry had a double suite. As displayed in the opening scene of the auto entrance and lobby shot on location, the hotel was ultra-modern. The elevators used bars and not buttons. The film's art director discarded the actual modern furnishings and decorations for Harry's suite, preferring more garish, fanciful rooms.
When Harry and Billie turn the radio on and off repeatedly during the Congressman's first visit, they alternate between using the left and right knob on the radio (actually they don't touch either knob but just wave their hands in the general vicinity of them).
The bejeweled Billie has been engaged to Harry for 7 years and yet not once is there a scene with an engagement ring on her finger.
When Billie and and Harry play gin rummy, she consistently deals him 11 cards to her 10.
Brock's luxury suite at the Statler Hotel (now the Hilton), on 16th and K Streets, NW, has a close-up view of the Capitol dome which could not possibly be seen from that angle across town.
When Billie tells Harry she's leaving, at 1:30:53 Harry calls her Judy.