On January 3, 2007, Rick Perlstein offered "Heck-of-a-Job Myers?" (link). It concerns an appearance by Immigration and Customs Enforcement (ICE) head Julie Myers at the University of Chicago Legal Forum, apparently in October 2006:

As labor unions increasingly provide representation for undocumented workers, [Myers] said, "we need to look at" unions' violations of the boundary between "charitable assistance and the unlawful employment of aliens." Several lawyers were soon on the phone with labor officials trying to figure out what she meant. Is an ICE crackdown on labor organizing drives imminent? Was one already under way? Were unions harboring undocumented immigrants in violation of the law?

...ICE spokesman Dean Boyd seemed a bit taken aback when reached by The Nation for clarification. "There is a fine line between organizing individuals, um, which is perfectly legal; however, once you cross that line where you might be involved in knowingly hiring illegal aliens, that's a problem." Then he reached for a bizarre analogy: mob lawyers. "We have had cases in the past, unfortunately, of attorneys doing the same thing," Boyd said. "Lawyers who knowingly accepted laundered drug money as payment for their legal services--going so far as accepting large plastic bags of cash." He compared that to a union "knowingly recruiting illegal aliens to join a company."... ..."Let's say there's a bunch of new employees, and some of them are illegal and the union organizer is an employee of the same company and is advising them, I don't know, on how to, for example, where they can get better fake documents," he fantasizes. "Or, 'I know your status. Here's a place where you can stay where law enforcement can't check.'"

As could be expected, Perlstein isn't able to get his head around the fact that unions - or groups like LULAC - might serve in some capacity before employment or in a non-traditionally-union way post-employment, such as by harboring illegal aliens. He was unable to find a past instance of a union being prosecuted for such actions, but it wouldn't be a bad idea to at least investigate whether some have crossed the line. However, since Myers made that statement over a year ago and I haven't heard anything along these lines since then I'd imagine they aren't doing anything.