On at least two default RedHat 6.1 install with all
packages, when shutting down from a user other than root
that user's password is accepted in order to proceed with
shutdown, rather than the root password.
Feel free to contact me for further information.
Is that user currently logged in at the console?
That is correct. Upon further examination, a user (other than root)
not logged into console is not able to shutdown on these machines.
What do /etc/pam.d/shutdown and