Administrator Vs User SIEVE scripts

        I assume all users can have sieve scripts to filter their mails.
In  
        addition to user specific sieve scripts, administrator/system
level 
        sieve script should also exist in order to override other user's
scripts.

        Does any of our SIEVE documents talk about this. 

        I guess multiscript draft should capture.
        Pls clarify. 

        Cheers,
        MG