Where recordings are made for the purposes of ensuring service quality, the institution should make it clear in its statement as to the circumstances under which the recordings may be reviewed. Recordings involving the voices of a clerk and a customer should not be used as training material unless the data subject agrees to it. There are other ways instead of using the recordings for training, such as having staff to mock the dialogue. In view of the principle of reasonability, it is advisable to avoid the use of recordings of conversations between staff and customers as training material.