Restricting root logins (/etc/securetty). ctl-alt-F4 will give you a prompt for tty3. Note
that it is one number less. Take a look at the contents of "/etc/securetty". To prevent
root from logging in on this device, take out tty3 from this listing. Note, you can always
login as another user, then, su to root.  Below is an example of the default
"/etc/securetty" that allows root to login to everything.

[root@squeezel ~]# cat /etc/securetty
console
vc/1
vc/2
vc/3
vc/4
vc/5
vc/6
vc/7
vc/8
vc/9
vc/10
vc/11
tty1
tty2
tty3
tty4
tty5
tty6
tty7
tty8
tty9
tty10
tty11