disable root autologin tty2 and tty3

[ARNAUDOV Krasimir (D3S)]

Hello,
Is there a way to disable root auto-login on tty2 and tty3?
During an installation someone can switch with Alt+F2/F3 the console and edit 
files.
One user has changed /target/etc/sudoers and gained root rights.

Regards
Krasimir Arnaudov