As the resident "OS X guy" in my company, I was recently asked by the IT department to help with a little problem. The IT department is upgrading its users to OS X. They don't want the users to have admin privileges, and yet the users should be allowed to change the date and time. This is especially necessary for those with laptops that do a bit of travelling.
OS X doesn't keep track of different time settings for different users; there is only one clock and OS X treats it as a privileged system resource. Now there are times when you would want a regular user to be able to change this preference, as when a user is travelling with a laptop, and times when you don't, as when you have some critical scheduling app running or what have you.
Unfortunately, OS X doesn't really allow you to control this. Sure you can lock and unlock preferences, but that does not persist beyond your "session"; once you logout or reboot, the preferences revert to their privileged state. I have made some progress in finding a solution; perhaps others can take it further...
In the /etc directory is a file called authorization. Apple eventually plans to add a GUI for this file, but in the meantime you must edit it manually. If you examine the file, you will find a section that looks like this:
<key>system.preferences</key>
<dict>
<key>group</key>
<string>admin</string>
<key>shared</key>
<true/>
<key>allow-root</key>
<true/>
</dict>
By removing the default parameters (robg adds: everything below the "key" line, I believe) and replacing them with just allow, you will allow all users to be able to change all system preferences regardless of group. You will have to logout and login for changes to take effect.
system.preferences.dateandtimebut nothing seems to work. Perhaps someone else can take it from here.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030729113134293