Add a websocket connection from the provider screens to the backend to listen for any No Fly Zone violations. When a drone updates it's position via PUT /drones/{id} and a nfz violation is detected, the backend should post the updates via the socket and frontend should display a warning.
The UI should reflect the severity of the event, for example a visual Bell (growl or background goes red). Also a popup with drone name, serial number and a link to drones map should be displayed, similar to this one
http://screencast.com/t/nrwBteb5toE5