Prince Philip Was Required to Walk Behind the Queen
Reason: The Orders of Precedence demand it
Exception: Informal situations
When you look at images of Queen Elizabeth II and Prince Philip, you may see that he was usually a few steps behind her. That is because Prince Philip was a consort, not a king. Because of the Order of Precedence, his rank to the Queen was lower, thus he had to show respect for the Order by trailing behind her while they were out together. Time will tell whether this custom will continue with Queen Consort Camilla and King Charles. In 2012, WBD labeled the Prince as “the man behind the queen.”
The monarch is not permitted to sit on a foreign throne
Reason: Mark of respect for the British monarchy
Exception: None, not even for fictional thrones
This is a long-standing, historic tradition, not a law (though the two may have equal force). Tradition dictates that British monarchs only sit on British thrones, never foreign ones. Stack Exchange and other sources describe this legislation as a “age-old mark of respect.” Queen Elizabeth took this regulation extremely seriously. When she was invited to the Game of Thrones set, she graciously declined to sit on the Iron Throne (although she admired its design).