I am an administrator of a Google Apps for Education account. When my users log in, they always receive warnings that their information can be accessed, modified, or deleted by an administrator at any time. I don't actually know what I can and cannot do with my users' information. I know that google-apps-improved-login was an option for a while, but what options do I have for modifying user information beyond the changes I can make in the Apps Control Panel?
As a super admin, you can change their password to something you know which gives you the ability to access, modify and delete any of their information.
Additionally, super admins gain access to other users' Google Sites.