Some of my colleagues, intoxicated with the success of downward spiralling smoking and lung cancer rates, are turning their attention to getting smoking either banned from movies (legislation is pending in Bollywood and all smoking on Thai TV is now pixelated) or slapped with an R-rating, assuring box office oblivion. The Australian Medical Association now suggests that state and federal government funding be withdrawn from films that “glamorise, feature or promote smoking”.

There’s a growing body of research that shows growing depictions of smoking in movies, and that kids who watch lots of movies smoke more than those who don’t, even after the studies control for social class and measures of parental strictness and supervision. The tobacco industry, starved of orthodox advertising vehicles, sees product placement in movies as a lifeline.

Professor Stan Glantz from the University of California, who has done much of this research and maintains an advocacy website on it, says simply “I just want smoking to be treated like the word f-ck in movies”. Others point to the longstanding classification of illicit drug use, hard-end violence and sustained humpy-rumpy as tickets to R-certification. Tobacco kills five million worldwide a year, so why not treat smoking scenes like injecting drug scenes?

But should movies, books, drama and entertainment generally be seen as simply part of some ideological state apparatus for promoting health, to be appropriated at will? If such precedents are set, awkward questions immediately arise about every single-issue “please don’t” area. No more shoot-outs, car chases, misogyny, cruelty to animals, racism, gluttony, sloth, unsafe s-x and anything promoting extreme, dangerous sport or leisure like mountaineering. Impressionable kids might get the wrong idea; movies would become nothing but anodyne vehicles for wholesome values. The Pyongyang Film School, the mecca for budding screenwriters and directors wanting to know all about falling in line with government policy.

At one stage, Diaz reaches for a cigarette. The sagacious MacLaine says “you shouldn’t smoke. You have a history of lung cancer in your family”. MacLaine takes the cigarette away, as a grandmother can. The scene said to me: many semi-anorexic, confused, glamorous young women smoke, and here is a scriptwriter taking the effort to make a point that we can all applaud.

But it struck me that if the movement to get all non-historical depictions of smoking R certificated (Churchill’s cigar is safe), then this powerful moment would be relegated to R-certificate. If that had happened, then perhaps thousands of young people around the world, lured by Diaz’s box office appeal in this and other movies, would be denied the richly contextualised and powerful message that the movie delivers: people who smoke are often very glam and cool, and drip with attitude but, like Diaz, they are often drifting, confused, and in the end, not particularly attractive characters. Hardly ideal role models that we ought to be rushing about trying to stamp into R certificated oblivion.

Would a panel of smoking classification adjudicators give this a green light as a state-sanctioned depiction of smoking because it didn’t actually show smoking, but just referred to it as it was about to happen? But what if Diaz had smoked heavily throughout the film, and then MacLaine had made the same powerful point and Diaz had stopped? What would the panel have rated the film? There would have been 40 minutes of glam-smoking, with one poignant moment that precipitated an apparent rethink for Diaz. Presumably the censors’ red pens would have rapidly doomed it as R.

I cannot imagine a smoking scenes panel who could ever dream up a code of on-screen smoking conduct that would be able to anticipate the richness through which creative people in cinema, literature and popular culture can codify complex narratives about smoking, for better or for worse. When we step into the dark waters of literary censorship, we need to be very sure of what we are doing.

Simon Chapman is professor of public health at the University of Sydney and last week won the NSW Premier’s prize for outstanding cancer research.