What does the seller do with it, then? There has to be some sort of sequestration program, possibly involving landfills - but a mass of cigarette butts is likely to produce runoff that's toxic to plants and insects, at the very least, if not to everything in its path. So, if you have a multiple-stream recycling program, you probably need to add a stream to that specifically for butts; if you have a single-stream program, I hope your sorters are getting hazard pay already, and if they aren't then they sure should be now. And you still have the sequestration problem from here - all you've accomplished is to make it minimally possible to implement that. And all of this costs, and everything downstream of it will cost, too.

Cheaper and simpler just to ban cigarettes entirely. And I realize that's neither simple nor cheap! But it's not the worst idea I've ever heard, either. Even back when I smoked every day, I wasn't entirely against it; now that I smoke only when drunk, I favor it considerably more. Yeah, it sucks to go cold turkey, but nicotine isn't like ethanol; quitting cold turkey makes you miserable for a while, but it's not going to kill anyone.