Instead of a kill switch Intel could have went with a Lo-Jack type system.

Nearly all laptops these days come with the LoJack bios agent pre-installed: http://www.absolute.com/en/products/bios-compatibility.aspx

Notable exceptions include Apple, Sony, and the Lemote Yeeloong (of Richard Stallman fame).

Interestingly, Absolute Software has no formal connection with the LoJack corporation other than licensing their name for the software.