Yes, it's true many members of the RF attend banquets for foreign head of states and receptions. Also it's very common to see other members of the RF attend Trooping of the Colours, Remembrance Sunday, Opening of Parliament, but aside; Phillip, late QMother, Charles & the late Margaret I don't recall the Q being accompanied by other members for event such as the upcoming Fortnum & Masons. I think it a brilliant idea. I do feel that Kate will learn a lot from closely observing another member of the RF especially the Queen. It's what I've been saying for sometime that she should be given the opportunity to shadow another member of the RF.
This is wonderful news. So glad to see that Kate is not being thrown in at the deep end like previous wives who married into the RF.