System shutdown from GDM

I'm using GDM (debian stable, gnome2.2 woody-backports), and for while,
i was able to shutdown the system from the login screen just by clicking
on *shutdown

After a recent set of updates, i now have to type in the root password.
I see the wisdom in making the default behaviour like this; however,
from my laptop, it isn't cool. I sometimes let my girlfriend or friends
borrow my laptop, and I am no longer able to ask them to shutdown the
computer for me without giving them my root password!

Any ideas? I'm checking google and my config files, but I can't seem to
figure out which file to edit, and which option to set.