Outside many establishments in Japan you will find an umbrella rack full of nearly identical translucent white umbrellas (the style sold for a few hundred yen at any convenience store). Many of these have been inadvertently left behind, the rain having stopped while the owner was inside.

Once I found myself in the reverse situation, sitting in a friend's bar when a downpour started. I asked him if I could take one of the abandoned umbrellas to get home, but he refused, saying they belong to his customers. He agreed that no one would ever come back to claim one, laughing at the absurdity of it, but he couldn't risk being discovered as the bartender who abetted the theft of a misplaced umbrella.