You can make it so that root can't accidentally delete or update a file, which is what I have done for some files, however, in vi, when I really want to
Esc:w! will override the current permissions.
P.S. But accidentally hosing your system is the #1 reason not to run as root. Well, maybe tied for #1 with security risk if you are on the internet. See Mr Ross' sig, well, don't try that as root unless you really want to re-install your OS or want to see just how long it takes your box to die.
Six simple characters on the command line. Now that is power!