To answer Dieselman's questions:
There is no Installation Mode. If you run an unrecognized installer, you will get one alert, and you can allow or deny the installer to run with elevated privileges. (If the installer is digitally signed, you can check Always trust the publisher of this file, and the publisher/vendor is added to My Trusted Software Vendors.) If you allow, you will see no more alerts for the installer, and the installed files will be trusted (added to My Own Safe Files).
Computer Security Policy and Network Security Policy windows are not changed, but they are not used much. CIS will not create rules for known safe applications (and applications signed by trusted vendors), unless you change that setting. Instead, My Pending Files and My Own Safe Files are used much more now (in Safe Mode too). When a process is automatically sandboxed, the file is added to My Pending Files, and can from there be moved to My Own Safe Files, if you want to trust it.
Ubuntu 12.04, 64-bit | Chrome 20β