2003: Locked-out Administrator account is unlocked

A locked-out Administrator account is unlocked if the correct authentication credentials are sent to Windows 2000 Server
http://support.microsoft.com/kb/838156

My note:
The "Applies to" section says that this issue is on Windows 2000 but I experienced this on 2003 R2 as well

When Administrator account is locked out, nothing appears on Event Viewer.
But failed authentications do appear as Event ID 675 (Source=Security Type=Failure audit)