I've never seen a $20 bill on the ground in my entire life, so I guess the economists are actually right.

I recently saw a $20 bill left in the bill dispenser of a gas station ATM. I didn’t take it because I assumed there was a chance that whoever left it would realize within a minute or two and run back for it. But most likely the next person to see it grabbed it.

I found 500 DKK on the ground outside once, which is about $77.