Please stop with this. The last time temp workers sued (and won) [1] the rippling effect it has had on 100s and 1000s of contractors since then, is that companies (in Silicon Valley and Bay area atleast) no longer employ contractors for more than 18 months at a time.
And due to this a lot of contractors since 1998 have had to leave lucrative contracts at software companies, because the companies that hired them specifically put this max limit after this lawsuit to shield themselves from such a law suit.
Personally, I've had to leave 3 separate contracts since 2006 in San Francisco, solely because the clients had this policy of not hiring temp workers/ contractors for more than 18 months, so as to avoid any lawsuit from temp workers suing for employee benefits.
[1] Source: [2000] Microsoft to Pay $97 Million to End Temp Worker Suit http://articles.latimes.com/2000/dec/13/business/fi-64817