My children and my grandchildren would stop that behaviour as soon as challenged
Isn't that what she did? It was dealt with and over in a few seconds, all played out in love TV.
I also work with this age group, and a little older, children do push boundaries and can have moments of cheekiness/rude behaviour, and most often down to their parents (as that's who they feel safest with.) it's a natural part of growing up and learning how to behave. He was reprimanded (in a discrete manner due to the location and being on TV no doubt) and the challenging behaviour was stopped very quickly. He was distracted and jollied along for the rest of the (very long) event by his parents and grandparents.
We saw a few short moments of rudeness which was quickly stopped by a parent. 🤷♀️