This appears to be fixed in Intrepid. With a guest session logged in, even from my own admin capable account I was given a warning that other users were logged in, and required to authenticate to initiate a reboot.
** Changed in: gdm (Ubuntu) Status: Confirmed => Fix Released -- Any user can reboot or shutdown computer when screen is locked https://bugs.launchpad.net/bugs/153706 You received this bug notification because you are a member of Ubuntu Bugs, which is a direct subscriber. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs