Ye ol' palm finger of the 1950s.. who could forget that? :)
I'm running a self-hosted Stable Diffusion, so there's no CLIP text encode word filters. It must be that they didn't include many smoking photos in the checkpoint models or weighed people smoking low in the training. I tried it on a handful of models, from realistic to artistic - nobody smokes. Holy smokes! Of course I had the car engine blowing smoke on a few lol.