I worked on a mental health ward. There were keys in the office drawer and in the drug cupboard. They were there for ages, and the numbers grew. I cleared out all the keys I could find in the office and locked them away. 2 years later no one had asked for any of the keys. Why did we have them? Why had people not needed them back? What happened? Did people go home? Did they go elsewhere? Did they have lots of spare keys?