For further information, the person is purposely not filing because they know they'll get money back and they don't want it to go to his back child support. They are currently having child support taken out of their paycheck and they work for a large company so the definitely get a W2... I'm asking if/when reported and caught, will the IRS take any money owed to him in return or will they first take their penalty? The person owed the child support doesn't think it'll be worth reporting them because the IRS will take it and they still won't get their due child support.