First let me preface that I have searched this network of Exchanges, and do not see an Ethics Exchange; this is the closest I could find.
One evening this week after work, I was grocery shopping. As I exited an aisle in the produce department, there - clearly visible to all - was a $20 dollar bill, folded neatly lengthwise and lying flat on the floor. Involuntary motor skills took over and I discreetly, but quickly went over to pick it up. Then the ethical part of my persona stopped to look around at my fellow shoppers, waiting for someone to claim it because they had just now realized it wasn't in their pocket.
I only lingered for about 5 seconds, and continued shopping. The last pang of guilt came when my usual cashier made a note that she should check the bill since I always paid by card.
As the bill was so clearly in the open, and how it contrasted the tile it was unmistakably money. To this day I feel this must have been a social experiment.
I have found money on the sidewalk before where there were far fewer people around. I have even found money on the floor in malls before. The difference between the mall and this grocery store incident was that the grocery store was quiet, and there was a sense of intimacy between me and my fellow shoppers (compared to the mall, anyway, where it feels like herds of cattle being driven).
So what's appropriate here? I am sure the right answer is to 'consider yourself lucky and move along.' But part of me feels it was wrong.