I bet they know. Non smokers can smell smoke on a smoker a mile away - or at least that was my experience when I was a smoker.
IMO
I know it sounds strange, but I have dated two different men that hated smoking, but told me they couldn't smell it on me. Hard to believe, but I have friends that if they smelled it they would tell me or ask me. lol
ETA--You know my trick and also lots of gum.