After a fresh install of OS 11.2 (x86_64) / KDE 4.3.1 "release 6" ordinary users where not allowed to mount USB sticks.

It was rather annoying to google outdated solutions and digg through various posts which are partly unresolved or IMHO provide too complicated solutions.

Related posts are:


Cause:

In Yast2
-> /etc/sysconfig Editor
-> Selection {{{System/Security/Permissions}}}
-> PERMISSION_SECURITY is set to ''secure local'' (That's what I do since OS 9.x)

>>> Therefore POLKIT_DEFAULT_PRIVS defaults to ''restrictive'' !

Solution:

In Yast2
-> /etc/sysconfig Editor
-> Selection {{{System/Security/PolicyKit}}}
-> Set POLKIT_DEFAULT_PRIVS to ''standard'' and run
Code:
set_polkit_default_privs
.. that's it.
The Yast2 help text explains all this, but then you basically already must know what's wrong.

...hope this might be helpful...

Reference:

Modifying Configuration Files for Implicit Privileges