This schema purports to be invalid on the grounds that the base type has a wildcard that is not a subset of the wildcard in a type derived by extension.

The base wildcard is

 <openContent mode="interleave">
  <any processContents="lax"/>
 </openContent>

and the extension wildcard appears in the schema document as

   <openContent mode="interleave">
    <any processContents="lax" notQName="hi"/>	<!-- invalid -->
   </openContent>

In the component model, the open content wildcard is the wildcard union of the wildcards defined on the base type and the extension type (which in this case is actually the same as the wildcard on the base type). The wildcard on the base type is a subset of this union wildcard, so it seems to me that there is no error.