Baker is an auditor for ABC Company. He is reviewing the expense reports that Green, a salesperson, has submitted over the last twelve months. Baker notices that Green's expenses for "customer development dinners" consistently range between $160 and $170, and the amounts are almost always a round number. ABC Company has a policy that limits reimbursement for business dinners to $175 unless otherwise authorized. In addition, most of the expense reports show that Green paid for the meals in cash, even though he has been issued a company credit card that he usually uses for other travel and entertainment expenses. What kind of expense reimbursement scheme is Green most likely perpetrating, based on these circumstances?
What internal controls would help prevent an employee from claiming an expense more than once?