In Aus, we don't allow ciggerette advertising on telly or on billboards etc (notice the Marlboro signage gone from the Ferraris at Albert Park?). Smoking is banned in most public indoor areas (movie theaters, restaurants etc) where the possibility of secondhand smoke causing problems (smell also!) is amplified. Outdoors its seen as alright. Whilst personally I'd be quite happy to see a total elimination of smoking, I can see that at the moment it sits at about the right level of concern on the "slippery slope" of rights vs public health. Me being judgemental and just deciding to eliminate smokers and the enjoyment (and knowledge of self harm) of smoking the habit gives them, IS attacking their right to smoke (as long as it doesn't affect anyone else). So the right I'd be stopping is their right to smoke, which WOULD change their (immediate) enjoyment of life and make them pissed. They would slowly get used to it and not care after a while - hence the SLOW turning of the wheel to gradually stop folks smoking. It will happen eventually I think (or you just won't see it in public...).
With seatbelts, there is no real amazing lifestyle 'plus' or spectacularly immediate enjoyment in not wearing a seatbelt (other than you can). You're still sitting there, you're still just driving a car. Protecting kids who don't have the choice whether they die or not is also a big plus here. So basically there is no important "right" (besides principle - no real lifestyle hit) that's being impinged with having a seatbelt law. Unless one is physically incapable of putting on a seatbelt and gets a fine subsequently!! Personally, I don't think the concept of fining people is ideal, but it seems to be the only way to get them to buckle up consistently. What I am in favour of is fining them for not suitably restraining a child or baby. The kid's right to live is FAR more important than the parent's right (according to danoff etc) to kill them.
Its quite funny how people fear the subsequent 'fine' for not buckling up more than their own life being lost. They need to get some perspective... Most people are only concerned with their immediate enjoyment (smoking) or immediate fears (fines etc - remember, they think they're invincible on the roads, despite the stated road tolls being a constant in the equation). They need help to see the long-term danger or potential risks they take at their own and other's expense (seatbelts/smoking laws). This is why I see the government's role as making society safer (whilst trying not to make everyone miserable!!) as extremely valid. Everyone knows that the old fashioned "everyone for himself" mentality doesn't make a very good place to live in. Ok now I'm gonna say something silly - you fear the ghost of communism so much that you're illogically unwilling to care about others in a humane way. I know this is pushing it, but hey its an interesting concept for why American society is so right wing and selfish currently (yes I know Kerry was crap and this statement is valid for Australia too!).
The reason smoking isn't banned but seatbelts are enforced is possibly added 'theatrical drama' of a sudden death compared to one's health slowly degrading over a prolonged period. Society can't see as easily the direct implication of smoking a ciggarette and its effects. Mind you, I think smoking is a surer way to kill yourself than not wearing a seatbelt! It'll potentially take far longer... but it WILL work eventually. I think smoking should be bumped up a bit on the scale of concern.
Another reason why seatbelt wearing is enforced is that you have to be a certain age to buy a packet of smokes, so very young children have a right to be protected from smoking. The same for car accidents. A very young child should have a right to have their seatbelt on at all times when in a car. I believe that every person should have equal oppurtunity to prosper and have a good life. I know this concept is strange to danoff but I believe that the safety of a child shouldn't be left solely up to the mother (who may be totally drug-crazed and off the planet). Hence child protection services exist. Basically Danoff's views are consistent (and so are mine, but are harder to explain concisely - as soon as you admit you care about your fellow citizens it gets complicated very quickly - how much do you impinge and/or help in every situation? This balance is hard to work out, but I believe its immoral to avoid these questions. Every man for himself is far simpler, but doesn't work at all), but in the long run Danoff and Famine are happier with an uglier and meaner world. I'm not calling them mean or nasty but the logical endpoints for their philosophies would be.