Maybe that's the thing - there's been lots of fairly casual events on this trip. And I think we mostly agree, that's where Meg's wardrobe shines.
So lots of casual events (or, at least, less formal) = winning on the clothing front. Plus, she's not pregnant this time and having to accommodate that - or at least, most likely not.
I think they declared early there wouldn't be a formal dinner. certainly no tiara, but probably not even anything evening wear - is there even a cocktail do/drinks reception on this tour? Or is it all connecting with the folk? - which they probably kind of felt they needed to do.