This is what you'd have done

As reported in The Christian Science Monitor, George Condash was visiting the ATM at a Michigan credit union when he discovered a box of cash marked "$40,000." Video cameras captured him putting the box of money into his car and appearing to drive away, but he was really parking to take the box into the bank.

Fortunately, the box didn't contain $40,000. It only contained $27,000. Apparently it was forgotten and left at the ATM by a security guard. The credit union was so thankful they made sure Condash got an undisclosed token of appreciation. "It's not mine and any honest person, I hope, would take it back in," he said.