Royal nuptials

It is reported that Kate Middleton has chosen her (unmarried) sister to be her "Matron of Honour" at her forthcoming wedding to Prince William.  I'm somewhat confused (so what's new?) because my understanding always was that Matron of Honour was a title given to a married woman performing the function of bridesmaid  - so unmarried = bridesmaid (the "maid" sort of gives it away) and married = Matron of Honour.  I'm far more worried about Harry being Best Man mind you!