You are mistaken. No version of Outlook would ever do this, thankfully.
No full versions of Outlook even had the ability to add recipients
automatically to your Contacts Folder. Only the long abandoned IMO mode of
Outlook 98/2000 did that. To automatically add the email address of people
you respond to to your Contacts Folder requires code:
http://www.outlookcode.com/d/code/autoaddrecip.htm
http://www.slipstick.com/contacts/addauto.htm