This is true on even micro of scales. For example, our neighbors fucking suck. They have no idea that trash day is once a week and leave bags out whenever they feel like it. People walking by (tourist traffic) see that mess and assume that no one cares if they, too, leave their shit there. It becomes an enormous, uncontained mound every week. The rest of the street is pretty clean, and stays that way.

Similar hypothesis for even just one single piece of garbage. When we first moved into our house, the old owners left a bucket next to the alleyway. I looked at it the first day and someone had put a single cup in it. Next day, another cup and some other shit. Few days later, filled to the brim with dog shit and a diaper. Clearly wasn’t a trash can. Most of those people wouldn’t have left their shit there if someone else hadn’t done it first.