DX, where you live, a wildfire is a major reality. Out here, not so much, but I see where you're coming from.
I hate that cars don't come equipped with ashtrays anymore, due to the majority of the population being nonsmokers who can't seem to figure out that an ashtray is a great place to store spare gas money and loose change from drive-thru's, leaving it up to the smoker to supply their own ashtray, and hoping it does the job. The car ashtrays available at this time are less than desireable. I do not own one, because I like being irresponsible.
I would almost have to agree that smokers are more prone to littering, using my husband as an example. However, I tend to go out of my way to clean up not only my own trash but other people's trash (people who leave their trays on the table at fast food joints really piss me off because I, like most of America's population, once worked at a McDonald's). So really, I think it's half and half and 100% dependent on the person in question.
---
Mediocrity at its most average.