Seems like most royals who smoke nowadays try to hide the fact that they smoke but it's becoming more and more difficult to do. Where do they hide when they smoke where no one can see them? Getting more and more difficult as many places don't allow you to smoke inside and going outside you risk getting caught.
It might seem that way, but I suspect because the general public do not appear to be able to cope with anything other than the mundane, royals do not smoke when out on public engagements. Having said that, it would be difficult to smoke a cigarette, shake hands, hold flowers and wave all at the same time.
Of-course, it is not a case of hiding their smoking or taking any risks as it is nothing to be ashamed of. However, palaces are huge and so are the grounds and there are plenty of places such as the sitting room, bedroom, bathroom, roof and acres of gardens or an outside area by the kitchen near the bins where one can have a crafty cigarette.
Whenever I smoke in public, being a good citizen etc, I am always conscious of smoking away from other people. At restaurants, I always have a cigarette between entree and pudding and go outside far away from other people. Oddly, as soon as I do, all the other smokers in the restaurant see it as their cue to go out too and one is never left alone!
I do find that many non-smokers have the annoying habit of standing right next to the cigarette bin outside Ipswich train station whenever I am there! There is another non-smoking bin further along and I wouldn't dream of standing there! As for the smokers, they always ask me for a light or spare cigarette, which is as equally annoying! So I do sympathise with royals who smoke!