You guys are misinformed: Most of the tests that the poster is referring to are not usable projects–they are exercises used to level the playing field for the applicants. Design is a tough profession to hire for, I’ve personally been burned by hiring someone based on their portfolio, only to learn that they took liberties (and implied credit) for work that they were only a small part of.
At Motorola we have recently been administering short in-office tests to our Interaction Designer applicants. Likewise Cooper Interaction is famous for their 2-part test (which hundereds of designers have taken off their website.)
A BFA or BA today is just not enough credibility for many of today’s design groups. I would argue that as Design gains legitimacy, accreditation/licensing becomes more likely… We’re probably experiencing the beginnings of that.