Yup, real life story. This happened to me.
I wanted to cash my refund check from college. I also had to pay rent that day. My refund check was $1100. My rent was $550 (Yeah, rent is high here). I wanted to withdraw $580, pay rent, and still have a little extra fun money for myself.
I went to XYZ bank. The teller greeted me and I presented her with an evelope. Inside the envelope was the following: (1) The refund check, (2) My deposit slip stating that I wanted $580 back and wanted to deposit $520, and (3) a post-it note stating in what denominations I wanted my cash back and asked her to put the money in the envelope I'd given her.
She studiously went to work. After a few minutes, she handed me back the envelope with the deposit receipt and the cash inside. I thanked her and went to my car. I drove off.
When I got to a stoplight a few blocks from home (XYZ bank is only an 8 minute drive from my house), I counted out the money. I counted $600 cash back. I counted again. $600. Again. $600. She had given me too much. I checked the deposit receipt, and she had deposited $520 into my account. This was clearly an error on the teller's part.
What would you do? Take the money back or keep it?
Click me if you want to find out what happened.