Some business is restricted only to "US persons"--citizens and residents. Employers are expected to read the published list and fire anyone on it whose job des

Some business is restricted only to "US persons"--citizens and residents. Employers are expected to read the published list and fire anyone on it whose job description requires them to be a US person. There is no defense for "we were not aware of this", because the register is the ultimate public record. The fact that the IRS could as easily notify employers directly that their employee has changed status is irrelevant. The list is published so that other people may also discriminate on the basis of changed citizenship status.