at_console permissions as implemented by D-Bus have some problems:

1) it is now fully redundant with PolicyKit and session tracking via
systemd/ConsoleKit

2) it uses a different mechanism than PolicyKit or systemd to determine
sessions and whether the user is on local or not (pam_console)

3) it was never widely implemented across so removing it
harmonizes D-Bus permissions on all supported distros

To that end, remove the at_console section of the D-Bus permissions,
and rely on session-tracking and PolicyKit to ensure operations are
locked down.

No changes are being made to PolicyKit or session-tracking, so any
operations denied by those mechanisms are still denied, and no
permissions are being relaxed.  Instead, this should allow remote
users who log in via remote desktop or SSH to inspect network state,
change connection parameters, and start/stop interfaces.  Obviously
if you are remote, you should not touch the interface which your
connection is using, but that concern shouldn't prevent all the other
nice stuff that you can do with NM.

https://bugzilla.gnome.org/show_bug.cgi?id=707983
https://bugzilla.redhat.com/show_bug.cgi?id=979416