Can GDM allow passwordless logins for specified users, in Ubuntu?

[Andy Stone]

Hi

I have been bit-by-bit migrating away from KDE and towards Gnome - and 
now that I have adopted Ubuntu as my prime desktop I have even more 
reason to do so.  The only thing left now is KDM.

I use it because I want to locally log in and not have to submit my 
password, which is possible under KDM.  This activity is obviously 
dangerous normally, but I am on a home network behind a very robust 
firewall so have chosen to run the security risk.

Does GDM in Ubuntu have the same relevant functionality, and if so how 
do I achieve this?  I seem to remember some time ago under a different 
distro I simply removed the user password (passwd -d username) for a 
particular user, and from then on GDM didn't ask for one.  GDM 
documentation seems to back this up.  However trying this in Ubuntu 
still results in being asked for a password.  Odd, or am I missing 
something obvious?  I can find nothing in gdm.conf to tweak...

Besides, I don't really want this hacky approach if possible, of 
removing a user's password completely.  I'd be much more comfortable 
with just having GDM not request the password for certain local users.

Thanks
Andy (n00b)