Got this in an E Mail. Worth a look

[Big Flounder]

This actually happened to my wife before. She payed with a debit card and pressed no for cash back. She looked at the receipt and saw the $20 and asked the cashier about it and she said I'm sorry. I didn't even notice it. She asked to see the manager and she told my wife that since the $20 is right above NO it is often accidently pushed if you use your finger. You should always use the stylus.