I opened up Gnome Settings -> Date & Time, and all of the options in this menu are greyed out. I understand that some settings such as automatic date and time might require root privileges, but simply changing the time format from 24-hour to AM/PM shouldn't. In either case, all the options are greyed out -- including the "Unlock" option which presumably would ask for the root password. In other words, all the options in this menu are unchangeable.
^Triage: * summary line prefix (assuming sysutils/gnome-settings-daemon) * assignment, and request for feedback (normally automated, according to the summary line prefix.