Well its interesting, as we roll all that stuff up into one family, the head of government, head of state, and head honcho. So the trick is to seem polite, not violate any real area but never be seen to be bowing, or scraping, or groveling. Odd, Jacqueline Bouvier Kennedy got away with a curtsy to the queen, but she was a special case, I'm sure it would not have looked right to see Michelle do it.