Reminds me of the story about when the textile mills used to pay everyone weekly, in cash. One week John opened his envelope, then turned to the paymaster and complained his envelope was $2 short. The paymaster responded, "Yes, last week I overpaid you by $2, so I just deducted it this week." John nodded and walked away.
The paymaster then called John back and said, "I could tell by your reaction you knew about the $2 overpayment. Why didn't you mention it last week?"
John replied, "Well, I'm a reasonable man. I'm inclined to let it pass if a fellow makes a mistake. But when he messes up two times in a row, it needs to be called to somebody's attention."