Comment 3 for bug 1072838

Same with Ubuntu Gnome Remix 12.10 - editing has no affect, editing greeter settings file either manually or with gsettings.

Not advised to edit user uid or /etc/login.defs file as workaround, to hide uid's, unless you never intend to lock your screen. If you use screen lock, after screen locks you can't log back in. The gnome shell lock is a wallpaper clock that you need to slide up out of the way to unlock. After you slide it up, although you can see your loging id and picture, you can't type in your password that field isn't activate. You also cannot execut ctl+alt+f1 to drop to cli, nor is there an option on lock screen for shutdown or restart. The user gets stuck there and is forced to do a hard shutdown. At least, I wasn't able to find any gradeful way out of that mess...!!! lol