Stringer Nailed it.
If anyone who was caught employing illegal aliens was looking at 10 years of serious jail time. And if those laws were enforced, we wouldn't have a problem.
Chase it right up the ladder, like they do drugs.
Catch the foreman in the act, get him to squeal on the factory operator, get him to squeal on the CEO, owners. Seize the assests of the company, and everyone see's jail time. Problem would go away in less than a decade.