You have to remember and consider though that smoking was not nearly as attacked and villianized in the 80's as it is today. It was before all the 'butt head' commercials and the lawsuits against the tobacco companies which brought about the onslaught of anti-smoking campaigns, and the no smoking laws in buildings. There has always been some sort of 'don't smoke' message going around but it was not like it is now. Back then, the 'cool' characters in movies and shows could still smoke, whereas today, with all the anti-smoking propaganda, now only the 'bad guy' in shows smokes (ever notice that?) and there are subtly laid anti-smoking messages in kids' shows, like 'who wants to go out with him, he SMOKES!!' So, what I'm saying is, back then there would have been no reason to conceal smoking to maintain a 'good' image. As someone who lived through the 80's as a teenager, an older age than most of you were, I can tell you that the 'goody' image you hear about in those days has been highly exaggerated by time and picking up a few words here and there in an article, you tend to form a view of them that wasn't really accurate. I don't think they ever set out to put forth that kind of image, it just happened, because of their well known religious beliefs and that they just weren't wild and outrageous partiers or as promiscuous as most of the other 80's rock stars were.
So, what I mean is, if they did smoke, I don't think they purposely hid it, it's just they never posed with a cigarette until it became part of the image in 1991. I also don't think any kid is going to start smoking because they saw someone on TV do it- they are much more influenced by their peers. Still, I have always wondered just when he started smoking, but not for these reasons. I'm sure someone can enlighten us.