There's a lot of etiquette to remember when meeting the Queen — do I bow or curtsy? Do I introduce myself or wait for Her Majesty to speak first?
It may not be in the official rule book, but we'd hazard a guess that "entangling Queen Elizabeth II in your scarf" is definitely a no-no.
That's exactly what happened to one poor woman during the Royal Windsor Cup at the Guards Polo Club over the weekend.
Hilarious photos show the horrified woman trying her best to rescue her long black scarf as it gets caught on the front of the Queen's outfit.