I remember when plastic trays fit into all the trash cans at restaurants. I remember offhandedly thinking this probably has an answer, but shrugging and moving on.
The solution seems obvious now: just make the trash holes smaller, so you physically can’t throw your tray away. My mind just automatically slips towards “well, it’s just common sense”, and i can imagine so many people matter-of-factly saying that exact thing.
But the truth is: nobody knows something until they’ve learned it. Presuming knowledge is “common”, and implying it spreads and propogates itself undermines how much effort it takes to maintain the large body of useful knowledge across most or all of a population.
Also: take pleasure in our little victories over laziness and entropy every day, even if it’s just the top of a trash can!