Problem

John Smith has worked for Dr. Bosworth for several years. John demonstrates a loyalty that is rare among employees. He has not taken a vacation in the last three years. One of John's primary duties at the doctor office is to open the mail and list the cheques received. He also takes cash from patients as patients leave. At times, it is so hectic that John does not bother with giving patients a receipt for the cash paid on their accounts. He assures the patients that he will send them a receipt. When the office is not busy, John offers to help Mary post the payments to the patients' accounts receivable. She is always happy to receive his help because he is a very conscientious worker.

Identify any internal control activities that may be violated in this doctor office situation.