When I was allowed to meet Prince William in Düsseldorf a few years ago, I had a very simple sentence in mind that we commoners should take to heart when dealing with royals: "Don't chatter and don't cheat"! That means it's not me who starts a conversation, but my blue-blooded counterpart. And: I don't throw my hand at the noble person in greeting or, best of all, pat him or her on the shoulder in a cool and courageous way, but the royal greets me with an outstretched hand. So far, so normal, that's what court protocol dictates.
Pure Emotions
But what happened in the stadium after the European Championship final was not normal: Those were pure emotions, to which the players indulged, and which Prince William also gratefully accepted and wholeheartedly embraced with his team rejoiced. So no royal faux pas, but nice, human togetherness and completely understandable.
Leah Williamson, the England defender, is in very good company, by the way. None other than the former First Lady of the USA, Michelle Obama, was so enthusiastic about William's grandmother, the Queen, in 2009 that she even put her arm tenderly around the elderly monarch's shoulder and hugged the monarch tightly!
Leah Williamson is in good company

The puzzled face of Elizabeth II spoke volumes of great astonishment back then!