title: why namespace types should not depend on nested namespaces types?
body: <p>In .Net naming guidelines (<a href="http://msdn.microsoft.com/en-us/library/893ke618%28v=vs.71%29.aspx" rel="noreferrer">http://msdn.microsoft.com/en-us/library/893ke618(v=vs.71).aspx</a>) there is this statement:</p>
  
  <p>"A nested namespace should have a dependency on types in the containing namespace. For example, the classes in the System.Web.UI.Design depend on the classes in System.Web.UI. However, the classes in System.Web.UI do not depend on the classes in System.Web.UI.Design."</p>
  
  <p>I would like to know: why?</p>