[CentOS] RHEL5 and CentOS 5 root logins

I found, under a 64-bit CentOS 5 workstation install, it is possible to modify /etc/inittab and add a couple of lines to prevent root from logging into the console.

I found, under a 64-bit RHEL 5 server install, adding the same two lines completely breaks the OS, to the point that a reboot after the lines are added, the OS brings you to a fsck-like prompt, and other things break, too. I didn't have time to look at the logs for specifics, if any were recorded.

Does anyone know if a CentOS 5 server install option permits locking out root from console login? Does anyone know of a way, in RHEL 5 Server edition, to prevent root from a console login?

Thanks.

Scott