Only tangentially related, but I am continually astonished by the absence of any sort of social norms surrounding cigarette butt disposal. I have (otherwise environmentally conscious!) friends who smoke, and I've personally witnessed them flick their cigarettes into gutters and on streets. As a serious question, without judgment: are there any smokers on HN who can explain the phenomenon?
For some people it's as simple as not wanting to carry around some dirty stinking cigarette butts. Portable ashtrays are sometimes produced, but they never seem to catch on.
And we shouldn't ignore the power of the really strong habit they've formed of flicking them away.