With too many royal protocols than a country's constitution, in addition to its traditions, the British Monarchy may not be able to brief all their foreign visitors, even the head of state of every country. That is why as the longest-reigning monarch to date at 93, Queen Elizabeth II might be immune to common mistakes that her visitors would do, especially the non-English ones.
During President Donald Trump's 2018 visit to the United Kingdom, Twitter was on fire as it listed all his mistakes, disrespects and probably merely almost all non-royals do not know. Fortunately, the camaraderie and unity within nations are still intact despite all these, as there has been no issue or royal announcements that have banned any presidents or high-profile visitor.
It started off with punctuality, just like in the world of professionalism, being late can be a very embarrassing habit and even ordinary employees lose their jobs because of punctuality and time management. When President Trump made his first royal encounter with Queen Elizabeth II in 2018, he was late, and body languages showed that the Queen found it distasteful when he walked before her during the inspections of troops.
Some of the comments were already hilarious but the State Banquet afterward gave President Donald Trump a chance to somehow make amends for his partly royal misdemeanor. With his speech, he was able to make a remarkable speech recalling the numerous occasions the United Kingdom and the United States of America were together to win over the Second World War.
The difference at the time of President Obama, the banquet he shared with Queen Elizabeth II in 2011 left the Queen in an awful shock as he spoke "nonstop" even as the British National Anthem began to play. When the part of "God Save The Queen" is already being heard, President Obama was still talking, not until he noticed the Queen's haunting stare.
Likewise, former President George Walker Bush wasn't able to erase the awkward question he asked her on the first time he met Queen Elizabeth II in 1991. Out of nowhere, he revealed to Her Majesty that he is the black sheep of the family and inquired her who she considers as the black sheep in the British Royal Family. The next time he had made a mistake of putting her on the throne for two centuries, he can only wink at her as he had added more than a hundred years to the Queen's age.
Queen Elizabeth II probably have no time to ponder on every mistake done by non-royals especially as she encounters a lot of them with her hundreds of engagements every year. But some has taken these issues to the next level as they thought that Her Majesty knows how to retaliate.
One story was told that the certain tiara of the Queen called the Burmese Ruby Tiara actually has a symbolic meaning of warding off evil and illnesses. During President Trump's visit in 2018, Queen Elizabeth wore the same tiara and though it might be meaningful, she has worn this tiara in the company of a variety of world leaders and for a number of different special occasions.