Actually, (and we've had this discussion before) the healthcare costs of smokers isn't really that much more than the average person as we die off sooner. It costs infinitely more to care for someone who lives to 95 with failing health than someone who dies at 70 from smoke related illnesses.
Once again, the healthcare costs of people who have health issues due to pollution from other sources is infinitely greater than those who smoked. I forget the exact numbers (and won't bother doing the research again) but last time I bothered, smokers put something like 1000 tons of pollution into the air and other sources of air pollution (I seem to recall just one coal fired plant in ontario) put something like 100,000 tons of pollutants in the air....and that's ALL smokers in Canada combined and just ONE source of air pollution. And don't even get me started on the amount of pollution caused by cars sitting idling on the 401 every morning. That brown haze over the highway isn't caused by smokers.......
Anyhow, as per the excuse that most vehicles don't have ashtrays any longer, I also do it so that the filter actually has a chance to decompose. What would you rather me do, wrap it up nice and tight in a plastic bag, put it in a landfill where they will dig it up in 1,000 years in pristine condition?
As for brush fires: unless I'm on a 400 series 4 lane highway, I make sure it stays in the middle of the highway and never throw them out onto the shoulder. Plus, and I hate to break it to you, but cigarettes are now designed to go out almost immediately if you aren't puffing on them. So the instance of a brush fire caused by a cigarette is pretty slim these days.....I seem to recall reading somewhere that older trucks produced hot ash from their exhaust that sometimes are still glowing causing a brush fire.......but you have no worry about that this year, not with the torrential rains we've been having......