You think there are people out there who will smoke, knowing that it causes lung cancer, because they figure government will pick up the tab for the chemo? Bizarre, but ok, if so, why doesn't having insurance give them the same incentive?
Pain pills are either A) not going to be strong enough B) harshly addictive. Probably opioids.
Nothing is going to stop her from quitting smoking, even if she was denied pain medication or surgery. They'd find other ways to numb the pain and just walk straight into an early grave.
Besides, if the prospect of lung cancer was enough to scare everyone off tobacco there would be no one smoking still. People are not always rational and yes I can see someone rationalizing their decision to smoke, in part, on the fact that if they do get sick they won't have to worry about paying for it. Or from the other direction if you know doing something could make you sick the prospect of simultaneous health and financial problems will be enough to push a larger portion of the public into making the healthy decision.