The techniques of this disclosure ensure user privacy when a user device with a camera is operated by a secondary user. Face detection and recognition are used, with user permission and consent, when a camera application of the device is in use. When it is detected that the device is being operated by a user other than the primary user, e.g., the device’s owner, enhanced security and/or privacy features are automatically enabled on the device. Using the techniques disclosed herein, faces within the viewfinder of a camera application are detected. If a face is recognized as that of the device owner while operating a rear camera of the device is in use, enhanced security and/or privacy features are enabled. Such features include filtering incoming system notifications, suppressing or obscuring other device or application alerts, limiting device usage to only the mobile camera application, etc.