Ron, if you're talking about companies operating facilities like meat packing plants, yes the illegal alien needs to steal somebody's social security number, and work on that basis, but it was my understanding that we were talking about construction.
                     The "company," as you put it, might be a developer, or he/she could be a general contractor. In either case, the work is let to a long series of sub-contractors--site development, framing, concrete, roofing, dry-wall, painting, plumbing, electrical.

                     The illegal aliens are usually working for these subcontractors, and that's where they're expenses are buried.
In California, during the recession of the early 1990's, a large number of the plumbers and electrictians were laundering money for crack cocaine dealers. They dealt strictly in cash. They'd buy all of their supplies and materials for Home Depot and Lowes, for cash, and pay their people in cash, and they didn't need to make a profit at all. The profit was in the coke.
                     An honest plumber didn't have a chance.

                     These are realities you won't find in Rupert Murdoch's Wall Street Journal.