It appears that the Internal Revenue Service plans to scrutinize 1042-S forms. The 1042-S is used to report payments made to nonresident aliens, along with any tax withheld.
The crackdown is in response to a report issued by Treasury inspectors last year criticizing the agency for paying out improper refunds to non-U.S. persons (our government at work again). There is no mention of legal vs. illegal non-U.S. residents payout.
Moving forward, before issuing refunds, the IRS will verify that the amount of withholding claimed by the nonresident alien matches that on the 1042-S filed by the withholding agent. That should cut down on fraudulent payments (the IRS hopes).
If the 1042-S is filed late, the alien’s refund will be delayed and IRS will levy a fine of up to $100 on the payer.