From a strictly military viewpoint, I've gotta wonder. I can smell a smoker from at least 10ft away in a no-wind condition, and can see big dark spit blobs wherever a "dipper" has offloaded. I will admit that I am from the "fight in the jungle" generation, not the desert, but it still seems to me that one could compromise his/her location simply by being a tobacco user...
_________________________
OBG