IMO
You can tell but you really can't.
I have looked at people and thought yup a definate smoker and yet I have been to parties of some diferent organizations and have personaly seen people who look like upscaled citizens like doctors, lawyers members of government who are just as quick to light one up. I personaly dont look like someone who smokes, that being said I dont even smoke in front of other people. Its the choice i have made to be safe! I go to places were people are doing it and when they ask if I want some I tell them I don't smoke even though I do. Its part of my famous fraze "TELL NO ONE" and sleep easy at night.
If people see that I dont smoke and I tell them I am not into it then who would believe a roumor that I grow it even though a roumor could not be told because I have told nobody! Everyone thinks I am the follow the straight line guy but really behind my own closed doors and no one else to see I am really a acomplished smoker!:evil: