Comment 21 for bug 221363

The problem with PolicyKit is that it don't alow a remote session to have privileges.
I already filled a bug while hacking the solution at https://bugs.freedesktop.org/show_bug.cgi?id=16510.

SSH creates a remote session. NX don't creates a session (my solution creates a
session on ConsoleKit, set active and set local).

To PolicyKit work you must have to be in a valid ConsoleKit session. ConsoleKit uses
the environment variable XDG_SESSION_COOKIE like:

$ echo $XDG_SESSION_COOKIE
f493e0b30e554108c3114c0046ffd1d0-1214412029.846197-1968504223

You can see ConsoleKit sessions executing:

$ ck-list-sessions
Session1:
 uid = '1000'
 realname = 'Marcelo,,,'
 seat = 'Seat1'
 session-type = ''
 active = TRUE
 x11-display = ':0'
 x11-display-device = '/dev/tty7'
 display-device = ''
 remote-host-name = ''
 is-local = TRUE
 on-since = '2008-06-25T16:40:29Z'

So if you don't set a active=TRUE and is-local=TRUE session on ConsoleKit
PolicyKit won't work.