Case Dashboard shows cases with deleted contacts the 'same' as non deleted

I was just trying to check if deleted cases & cases with deleted contacts show on the case dashboard. The former don't - the latter do. I'm not sure they whole behaviour - ie whether it should be possible to deleted a contact with an open case / how that affects the case. But it seems to me at the very least the contact should look deleted from the dashboard.

At the moment

http://drupal.demo.civicrm.org/civicrm/case?reset=1

shows 2 open cases - the appear exactly the same but one of the clickable contact links is to a deleted contact. In the attached pic you can see how the contact appears on the dashboard & on the recent links on the left