Login screen pretends to be user, screwing up scripts

When the computer is sitting at the login screen with noone logged in, scripts that run 'w' to find out how many human users are logged in get a report of '1' instead of '0' like they should.

An example of a script that does this is the checklogi.sh script here: http://www.mythtv.org/wiki/Using_ACPI_%26_MythTV_to_run_other_applications

The checklogin.sh script is used to prevent MythTV from shutting down the system when it is idle if a human user is still logged into the computer.

The fact that the GDM login screen pretends to be a user prevents shutting the system down when MythTV is idle and noone is logged in.

I have hacked the script on my machine to make this work, but it is not generalized and I can think of several cases where it will fail on a different setup.

The script was working on lightdm, but I had to switch to GDM due to a bug in lightdm that sometimes breaks xwindows.

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: gdm 3.6.1-0ubuntu1
ProcVersionSignature: Ubuntu 3.5.0-21.32-generic 3.5.7.1
Uname: Linux 3.5.0-21-generic x86_64
ApportVersion: 2.6.1-0ubuntu9
Architecture: amd64
Date: Sat Jan 12 09:44:28 2013
InstallationDate: Installed on 2011-05-22 (601 days ago)
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110427.1)
MarkForUpload: True
SourcePackage: gdm
UpgradeStatus: Upgraded to quantal on 2012-10-21 (82 days ago)
mtime.conffile..etc.dconf.db.gdm: 2012-10-23T18:59:34.443372