Members who have paid, but haven't yet gone through the signup system to get an account can log into the desktops as "signup". They will not be prompted for a password and they will be presented with FireFox? running in kiosk mode, allowing them to create an account.

The "signup" user has it's shell set to "/home/special/signup/session.sh" and is disabled so that no one can ssh in as that user. The session.sh script just starts firefox (which has the r-kiosk plugin installed) - the user gets no window manager.

Each desktop (currently with the exception of americium, uranium and neptunium) has an additional line in their /etc/pam.d/gdm file before the system-auth file is included:

auth sufficient pam_succeed_if.so user = signup

This allows the "signup" user to log into gdm without entering a password even though the user is disabled in the LDAP database.