I'm a monarchist, but have to agree that there is no reason for accusations of rabid republicanism on this thread. The issue is that the childcwas sweltering and uncomfortable from the start, (as can be heard in the video).
As a Headmistress of pupils aged 3 - 13, I spent 10 years considering what children should wear to events - full school uniform, with ties or without ties, sports kit, joggers, straw boaters, sun hats, sunglasses, home clothes etc. This was often in consultation with parents but I was also aware of the school's reputation in public and of the rules at the venue we were attending. BUT first and foremost was the requirement that the child should feel comfortable and neither too hot nor too cold. I would be very surprised if someone - K & W, the nanny, grandma Middleton - hadn't given the outfit some thought in advance.
But for me, the bottom line is they got it wrong.