Can an Individual Tax ID Number be used in place of a social for employment by a non-citizen?
An employer should not accept an ITIN in place of an SSN for employee identification or for work. An ITIN is only available to resident and nonresident aliens who are not eligible for U.S. employment and need identification for other tax purposes. An individual with an ITIN who later becomes eligible to work in the United States must obtain an SSN.
Consequences will depend on the facts in each case. Some of the possible consequences may include, among others, deportation, fines, or fraud-related charges. I suggest you consult with a local immigration attorney who can review all the facts and document involved.