[gravescale]

In a common area, drunk people and children sloppily doing a chore they don't want to, I should think. And depending on how grotty users of the space are, people leaving cutlery in dirty piles of crap for others to clear up, and the others don't see the hiding cutlery. The cleaners in my old university accommodation would remove dirty dishes to a box outside called the Stank Tank as it wasn't their job to do student washing up. After a month, it was binned or scavenged and a lot fancier stuff than a teaspoon was in there!

I can't say I've thrown away a spoon knowingly myself, but I have dropped cutlery in the bin once or twice. I haven't ever abandoned it but you can imagine people might if they don't value it. And based on the university, some people would happily lose a £30 pan rather than reach into the Stank Tank, so I can believe it.