Lately Facebook was added a number of New Sites feature for mobile application, Including Nearby Friends, Feature that allows users to Share uiasca location with friends (or more precisely notifies friends a user when he is near them). Given that this feature is one optional (It is up to the users if they want to use it or not) to be functional and friends will obviously have it work the mobile application used on smartphone provided (the feature can specify exactly location a user if he chooses to share uiasca location on map for a certain period of time).
With the feature enabled, it will not be automatically disabled, but the user will need to off manually then you will not want to make their location known. To Nearby disable Friends in Facebook mobile application (Both Android and the iOS), Please tap the More> Nearby Friends> Location Settings> Location Sharing (That way you can keep a record of location you, but it will not be shared with friends look on Facebook).
If you feel Nearby Friends as a feature that violates your privacy and do not want to use it to locate or be located by friends (location can be shared with friends, or watching public) Then you just need to let deactivated (As it set by default), Or off using the instructions above. If you do not mind watching location with friends Share on Facebook, but are irritated by Notifications displayed this feature, you can disable push notifications giving tap on More> Account Settings> Mobile Push.
Note: To reassure users that considered a violation of privacy Nearby Friends, but you can not help but use this feature, Facebook assures them that they could always delete it recorded data servers social networking directly from the application settings Mobile.