The Urgent Install button also falls in the “fake site hints” department. Still, if the user persists in installing the “update”, he will get a file called WindowsUpdateAgent30-x86-x64.exe.
At present time there is no report on how much harm the file in question can do. F-secure only stressed out that the file was not signed by Microsoft, and left everything else up to everyone’s imagination.
Nevertheless, it goes without saying that nobody would set up such a site just for fun, so keep an eye out for any such “urgent” offers.