Hide local admins at the login window
Proper text editor (like TextWrangler - OS X or notepad ++ - Windows)
Make an empty Fileset with a script that runs at activation.
Use this code as an example of how to hide admins at login, and also show the "other..." option at the login window to still use the local admin account.
# This script is a Postflight sample
# benm @ fw
#hide the just made admin account and enable screen sharing
echo "hiding local admins at the login window"
#enable hidden admins
sudo defaults write /Library/Preferences/com.apple.loginwindow Hide500Users -bool YES
#enable "other..." option at login window
sudo defaults write /Library/Preferences/com.apple.loginwindow SHOWOTHERUSERS_MANAGED -bool TRUE
To show admins at the login window again. Send out:
sudo defaults write /Library/Preferences/com.apple.loginwindow Hide500Users -bool NO
For more help see: Add FileWave Custom Inventory fields remotely using a Fileset