Custom filter view to show unassigned cases not working

Hi,

I am using version - 7.0.0 Build 7002

I have created a new custom filter view that is using the following options;

1. Request status is not closed, resolved, development fixed
AND
2. technician is not simon, robo technician

This view should basically show me all my open, onhold, waiting for customer, development, etc cases plus any unassigned cases

The problem is when new cases are automatically created by someone sending an email it makes the technician field set to 'none'.
As you see in step 2 I didn't enter technician is not 'none' so it should include the unassigned cases with a technician of 'none'

Am I doing something wrong or is there another way to do this?

Thanks
Tom