In SmarterMail16.2.6442 user can not over ride the anti spam settings unless the domain admin account has first overridden the spam settings.

The domains are set to allow 'Users to override spam settings' but this functionality is greyed out. The only way to activate it is to first login as the domain at and override the spam settings, once this has been done then users under that domain can then also override the spam settings.

 

This was not how this worked previously and seems to be a bug that users can not just override the spam settings without also the domain admin account first overriding the spam settings.