It is not uncommon for a dress-code to be semi-gala, meaning men with miniature orders, ladies with long gowns/tiaras.
There are many examples of events where ladies wear gowns and tiaras but no orders.
--Previous Message-- : : : --Previous Message-- : Wow! : : It is only the second time that the Duchess : of Cornwall wears this huge Greville diamond : necklace (after a CHOGM summit in Africa in : 2005 or 2007, if I well remember). : : : You are right, Arthur. The Duchess dazzled : with the Greville necklaces (it are two, : actually, a two and a three row one, fitting : in length to be worn together) for the first : and (publicly) the only time at the Gala : Dinner for the CGHOM in Kampala back in : 2007...and you know what? She even wore the : same gown back then . : : From gettyimages : : : : http://cache2.asset-cache.net/gc/78075538-royal-trip-commonwealth-heads-of-government-gettyimages.jpg?v=1&c=IWSAsset&k=2&d=CSIMBv%2faraCCLNLdbJQvXlSRBFwxmP9iehGAPdpAEp0Q733HaAjHJpdHVtheLTRqBG%2fHQ4gNdYOIKStKkQwoNA%3d%3d : : : : Yes Nellie, it surprises indeed, that The : Duchess wears no order . Maybe they were in : a hurry to leave and then the decorations : went forgotten ... : :