Hasn't HM Queen Sofia of Spain tripped and fallen in public several times...once in front of President and Mrs Clinton at the White House, and again as late as a few weeks ago?
As for Charlotte Casiraghi, this is the first I have read about any clumsiness..I have seen her ride and as an equestrienne she is the picture of poise and elegance.
Also, I remember reading somewhere that Fabiola, Queen of the Belgians almost dislocated her tiara while trying to get into a limousine, then another time she embraced another female and HER crown got tangled up with the other woman's?
If you ever see a photo of the tiara involved in both incidents you would understand...it is the Spanish Wedding Tiara and it is spectacular.