Maybe the Royal family will provide Obama with Zone 2 videos of the wedding and return the Medal of Honor that General Pershing presented to the British Unknown Warrior in 1921.
The royal family has a special attachment to Britain's Tomb of the Unknown Warrior. In 1923 Elizabeth Bowes-Lyon (Queen Elizabeth's mother) laid a wreath on the tomb on day of her wedding to the Queen's father. She did it in memory of her brother, Fergus Bowes-Lyon, who was killed at the Battle of Loos in 1915. Since that time it is a royal tradition that the bride in any royal wedding, including Princess (at that time) Elizabeth when she married Prince Philip, lays a wreath at the Tomb of the Unknown Warrior on the day of her wedding. I'm sure Kate Middleton will be continuing the custom.
So, no, I don't think that the royal family will be insulting the honored dead, General Pershing, the American Medal of Honor, or the American people by returning the Medal of Honor, as you suggest, just to stick it in Obama’s eye.
And if they were to do that, it's not like Obama would care anyway. Which I'm sure they know.