title: How can SystemInfo.deviceUniqueIdentifier be unique?
body: <p>According to <a href="http://docs.unity3d.com/ScriptReference/SystemInfo-deviceUniqueIdentifier.html" rel="nofollow">http://docs.unity3d.com/ScriptReference/SystemInfo-deviceUniqueIdentifier.html</a>, <code>SystemInfo.deviceUniqueIdentifier</code></p>
  
  <blockquote>
    <p>It is guaranteed to be unique for every device (Read Only).</p>
  </blockquote>
  
  <p>If you delete and reinstall your application, this value will change. <strong>How can it guarantee that there isn't another iPhone in the world that happened to generate the same identifier?</strong></p>
  
  <p>(I know that the identifier is pretty long so it is quite unlikely for this to happen - but I'd like to know why)</p>