You can disable the metadata tab by adding the following ignore rule to the Glimpse configuration
<glimpse defaultRuntimePolicy="On" endpointBaseUri="~/Glimpse.axd">
<tabs>
<ignoredTypes>
<add type="Glimpse.Mvc.Tab.Metadata, Glimpse.Mvc3" /><!-- or Glimpse.Mvc4 -->
</ignoredTypes>
</tabs>
...
</glimpse>