This may be of interest. It's a supply chain Digest story about IFCO and it appears to be a warning for shippers to clean up their act.
http://www.scdigest.com/assets/NewsViews/06-04-21-1.cfm
The Impact: Public attention is increasing – if you are employing large numbers of illegals, you might want to quickly make other arrangements and consult your attorney.
The government said that more than half the company’s 5800 U.S. employees were thought to have false or incorrect social security numbers.
NotE: Not one word about how many got out in 3-4 hours sure!