Yes, if you're going to be a Jeopardy contestant, or if you're going to a court trial, or to church, or to a wedding, or to an interview for a job in law or finance, or to a dinner at the White House or to Buckingham Palace, you should dress well to show respect.
That little stunt at the Oscars was clearly staged. They had that one guy dressed very casually in a sea of formality just to guarantee you would notice him. You could make yourself the center of attention just as easily in America by dressing formally in a casual setting or environment.
Here are some fictional characters known for dressing formally all the time:
-Gomez and Morticia Addams
-Count Von Count
-Elsbeth Tascioni
-Barney Stinson
