Yeah, I agree with the sentiments that a PC exposed to smoke can be really nasty. My younger brother and stepfather smoke, and their PCs look pretty bad after a while, especially my brother's (my stepfather's doesn't get all too bad considering how much he smokes). My brother's gets pretty bad real quick (he smokes alot too, along with all of his friends in his room), and I warn him "make sure you clean it" (I'd advise monthly myself, but don't let it go more than three or four months, maybe twice a year at absolute most). He doesn't listen. Last time I saw it and mentioned it, I told him it was probably about that time, and he agreed with me, but I know he didn't do it. I told him I'm not cleaning inside it again. It looks ridiculous, and I won't deal with it. Smoke bothers me enough as it is.
Smokers are (or should be) aware of the damage it causes, and it extends past just people. They should have to live with it. If it damages their PC, that's honestly not something the OEM should have to cover for them. I agree that maybe the OEMs should start explicitly stating a policy on smoking itself if this is what they intend to do, because we are dealing with idiots (not referring to smokers, but people in general when it comes to these things). I think too little people understand that smoking does do alot to the inside of a PC. Then again, most people don't know that PCs should ideally be cleaned regardless because of dust, so that doesn't help matters.