A large department store has just discovered that the staff in the store coffee shop have been defrauding the company for the past three years. The six employees who work in the coffee shop have been keeping a proportion of the cash takings, concealing the theft by not recording all sales up in the till They shared the proceeds of this fraud between them The fraud was only uncovered when one of the employees left and his replacement reported the theft to management rather than becoming involved in the crime

Which of the following best describes the role of the store's internal controls in the context of this fraud?