Geotagged notes app for iOS
I turn on and off location services when the user enters and leaves the master view. The user can only add a note from the master view, so this gives the app enough time to grab an updated coordinate while not wasting battery when the user is reading notes or looking at the map of where his or her notes were.
When the user has disabled geotagging for the app, he or she can still add notes, but they simply will have a null coordinate and will not show up on the map view.