Labor conditions for California's farm workers

From the Economist this week (no link to the actual story), a report on new rules in California, providing somewhat improved conditions for farm workers. Can anybody corroborate the following anecdote? If true, this is evil:

Farmers rarely hire their migrant workers directly; instead, they use labour contractors who will supply workers as and when they are needed.... The problem is that there are few safeguards against unscrupulous contractors who cheat their workers, for example by denying them their legal break-times or by underpaying them. And what compounds the problem is the understandable reluctance of undocumented workers -- the polite term for illegal immigrants -- to complain, even though federal agencies exist to protect all workers, legal or not. The AFL-CIO recalls that in July in North Carolina the Immigration and Customs Enforcement Agency arranged a phoney "mandatory" meeting of the Occupational Safety and Health Administration -- and, to the dismay of the genuine OSHA, promptly arrested the illegal immigrants who dutifully turned up.