Dai un'occhiata ai file in /etc/cups
Non ho un sistema Fedora 15 a portata di mano, ma guardando una recente scatola RHEL, i bit rilevanti sono in /etc/cups/cupsd.conf
....
# Administrator user group...
SystemGroup sys root
....
# Restrict access to configuration files...
<Location /admin/conf>
AuthType Basic
Require user @SYSTEM
Order allow,deny
Allow localhost
</Location>
....
# All administration operations require an adminstrator to authenticate...
<Limit Pause-Printer Resume-Printer Set-Printer-Attributes Enable-Printer
Disable-Printer Pause-Printer-After-Current-Job Hold-New-Jobs
Release-Held-New-Jobs Deactivate-Printer Activate-Printer
Restart-Printer Shutdown-Printer Startup-Printer Promote-Job
Schedule-Job-After CUPS-Add-Printer CUPS-Delete-Printer
CUPS-Add-Class CUPS-Delete-Class CUPS-Accept-Jobs
CUPS-Reject-Jobs CUPS-Set-Default>
AuthType Basic
Require user @SYSTEM
Order deny,allow
</Limit>
IIRC, @SYSTEM è una macro per i gruppi elencati in SystemGroup