title: Do observers need to be removed in iPhone applications
body: <p>I subclass MPMoviePlayerController. In that class I attached all possible notifications that I need. <code>DidFinishPlayback</code>, <code>ExitFullScreen</code> etc. in it's loading method. My question is, if I want to STOP movie and dismiss movie player view can I (and do I need to) remove observers in <code>moviePlayerPlaybackStateDidChange</code> method on <code>stateStopped</code>? What can happen if I don't do that?</p>