We found within People and Groups a "Group" called NT AUTHORITY\Authenticated Users. This group is created automatically on new site collections also. Please DO NOT confuse this with adding this as an id for groups that want to added everyone to their site.
This is a group listed as if it were "Viewers" or "Owners". This group is not assigned permissions to the site it looks like but I am concerned as to why it is there in the first place.
To get there you go to Site Actions - Site Settings - People and groups - click on More... on the left navigation.
