Technological progress allows us to equip any mobile phone with new functionalities, such as storing personalized information about its owner and using the corresponding personal profile for enabling communication to persons whose mobile phones represent similar profiles. However, this raises very specific security issues, in particular relating to the use of Bluetooth technology. Herein we consider such scenarios and related problems in privacy and security matters. We analyze in which respect certain design approaches may fail or succeed at solving these problems. We concentrate on methods for designing the user-related part of the communication service appropriately in order to enhance confidentiality.