As an aside, I've seen this happen elsewhere as well. Classic play for wage theft. When I was working as a bartender in London to make ends meet, I had a coworker from Mexico on an expired visa. Great guy and the most hardworking. Well won't you guess it, guy got picked up by immigration authority on payday.
That would be bad for the company, but likely way worse for the illegal immigrants. Being illegaly exploited doesn't make them legal, so reporting the company to the IRS almost definitely gets the workers deported.