Why Vista wants to shut out other OSes

Why Vista wants to shut out other OSes: "On a drive up to Birmingham in the mid-'90s, Ross Bentley and I figured out that an easy way around file-level security on Windows NT is provided simply by installing a second instance of the operating system. An administrator of the second instance, e.g. the installer, can take ownership of files created on the first instance then do with them as they please - except they cannot give ownership."