<human>: I was making a cash payment on a credit card through a bank teller.  I gave her my credit card plus $1,300 in cash.  

She counts the money, prints a receipt and proceeded to hand me the card, receipt, and the money back to me.

In shock, I stood there for a second thinking, is she serious?  Then I told her, "I think you forgot something," and gave the cash back to her.  

I could've easily walked out of the bank with the money that she accidentally handed back to me but knowing she'd easily get fired on the spot for that mistake and the fact that they'd probably trace it back to me and ask for the money, I decided to do the decent thing and give her the money back.

If I was a prick, would I have been in the clear if I was to keep that money and say that I had no clue where it went?  Could I say I wasn't thinking clearly and was in a rush so I took the money not realizing what just happened?  Would the police get involved?  etc etc.

Give me a shortened version of the text
<bot>: Gave cash to bank teller for payment on card.  She processed the payment and accidentally handed back the cash to me.  I gave it back to her.  Was I in the clear if I kept it?