From http://ubuntuforums.org/showthread.php?t=716201:
Policy
Tutorials explaining how to enable the root account for a graphical login or autologin will not be supported on the forums and will be moved to the Jail. Although we believe people should have the freedom to run their computers however they want, we also believe in supporting Ubuntu's security model. You can find or post information elsewhere on the internet regarding graphical Ubuntu root logins; such tutorials do not have to be hosted on the Ubuntu Forums.
Users posting such tutorials after this announcement will be given a warning or infraction at the discretion of the staff.
Should we adopt that and close questions like How to enable root login?