Can anyone who has upgraded to Mountain Lion confirm that software updating is now done through the App Store and no longer through the Software Update utility?
If this is the case, does this mean different family members must sign in to the same account or use the same account just to update the OS? In my case, purchased OS X Lion with my Apple ID, one of my family signed to my account once in order to download Lion, but they can update their system using the the classic Software Update utility afterwards. Now it seems they'll need to sign into my account every time for any update, or we'll have to create a new Apple ID just for this purpose.
Best Answer
OS updates are in a different group in the Mac App Store, and neither checking for them nor downloading them requires you to be logged in to any account at all, so you should not have any problems.
Also note that you could simply enable automatic updates in System Preferences to avoid having to manage OS updates yourself.