Often for multi-user systems or for special purposes, Xfce kiosk mode is used so that you can disable all shutdown options for users such as hibernate and suspend. I am running Xubuntu 12.04, but with the ppas for Xfce 4.10 and 4.12. I think there were some issues with kiosk mode a while ago, but it seems to work again now, at least in my tests (see the before and after screenshots below).
Kiosk mode does not need any additional downloads or installations, but will only take effect if you have
/etc/xdg/xfce4/kiosk/kioskrc, so first run
sudo mkdir /etc/xdg/xfce4/kiosk
sudo touch /etc/xdg/xfce4/kiosk/kioskrc
There can be several sections of the
kioskrc file, but we will concentrate on
xfce4-session, as those are the settings you require. The official documentation is useful in explaining the options available for
xfce4-session, but below is an example of the possible content of the
xfce4-session part of
/etc/xdg/xfce4/kiosk/kioskrc. This would give you a really strict kiosk mode that would leave non-administrative users without any ability to shutdown the machine (or use suspend/hibernate) using the menus or via commands in terminal, although they could still logout. You may not want to use these settings, this is just an example (see below for further explanation):
In place of
Shutdown=NONE and other settings, you could very reasonably specify your own main user (e.g.
Shutdown=mike), so only you still have the ability to suspend/shutdown using the menu (without resorting to using sudo with command-line shutdown equivalents), but it depends on your purposes. If you want to specify groups use
%groupname, and for users just specify
username; the settings
NONE are self explanatory.
kioskrc with your text editor:
sudo nano /etc/xdg/xfce4/kiosk/kioskrc
Then copy the above block of settings for
xfce4-session, making sure that you alter the values to suit your purposes. Then save the file, logout and login again with your user or another user to test the settings.
My example of 'before and after' with the strictest kiosk mode settings, which will apply to all users:
a) Before with normal Xfce settings, running as user mike:
b) After, with kiosk mode and strict settings enabled, running as user mike:
For more information, please see the Xfce documentation.