Does hardware need its own open source license?

Slashdot reports that MIT has recently released some of its hardware designs under its own MIT license. (Pictured, Nick Negroponte as seen through an H.264 codec.)

The license seems really good for this purpose because it says you can mess around with the hardware, but they're not warranting it works.

Given a lot of the hardware I've seen this is a wise license.

Others in the hardware open source game, like OpenCores, prefer the GPL. The GPL states that if you make the hardware work you have to show everyone how you did it, so they can too.

While there are a variety of alternative licenses for content, notably the Creative Commons license, there is no alternative scheme as such for hardware.

Should there be? Is there anything intrinsically different about hardware, any hardware, which should require a special license to fit the case?

Whether you're practicing Copyleft or copyright, should hardware and software licensing schemes be the same? Or how should they differ?