What happens if you are a good citizen and as an example, a homeless person is rummaging through the garbage and the cigarette with your DNA on it goes into the

What happens if you are a good citizen and as an example, a homeless person is rummaging through the garbage and the cigarette with your DNA on it goes into the street. I guess it's a good way to make people think before they decide to litter, but in no way can it be accurate.