Here we have a photograph of some hostel rules in Jyväskylä, Finland. Our interest is mostly in the rightmost one depicting the smoking ban. This drew our interest because, very untypically, we have a smoking ban with an unlit cigarette! Often various smoking signs depict a smoking cigarette with the classical slashed circle "NO" symbol on top.
Perhaps in this case when the cigarette is not just a silhouette but a more detailed image, it is clearer to identify without the smoke? Though it still feels a bit off, since usually what we want to forbid is the adverse effects coming from the smoke, not the physical cigarettes themselves.
Note also the leftmost ban on partying (and implicitly other loud noises), where a smoking cigarette is used to convey the idea of a (rowdy) party.