Similar to bug #651168, I believe /etc/cups/printers.conf*
should be ignored by default.  From the manpage:

       The  printers.conf  file defines the local printers that are available.
       It is normally located in the  /etc/cups  directory  and  is  generated
       automatically  by  the  cupsd(8)  program  when  printers  are added or
       deleted.

Notably, this file includes all printers being broadcast on
the network, without any intervention by the user.

Cheers,
Edward

Edward Z Yang wrote:

This has been discussed before, in http://bugs.debian.org/568090
and at least /etc/cups/printers.conf seemed to be a real config file
that the user could legitimately edit.

There's also http://bugs.debian.org/549673 on cups.