Are you serious?
In NJ it is the law. The courts have made a public policy finding that making sure all emplyees are covered trumps other considerations. This drives up the cost of an employer carrying comp insurance, which is mandatory of all employers. One can make the argument that hiring illegals at lower pay offsets the higher cost of the insurance premium. And yes, some schools in NJ are highly burdened by illegal aliens. And yes, realtors are showing listings by the room. Seeing it first hand.
Before we moved a house (small 2 bdrm) was purchased across the street by a man who brings in illegals. Soon 12 to 14 were there. They boarded up the 3 car carport with cardboard, metal, whatever. Some moved in there. They built 3 sheds under 12x10 (zoning law size). from junk. Some moved in there. Some left each day for work, I assume. The one woman and babies were on welfare. They all may have been on welfare because if you are not on the payroll paying taxes, you can claim no income.
It's a mess. Totally destroys a neighborhood in about a week. And that was Southern Oregon. I can't imagine LA or Arizona.