"You may NOT require your employees or potential employees to use Self Check or myE-Verify under any circumstances. Requiring applicants to provide proof of their employment authorization before they accept an offer of employment is known as “pre-screening” and it may constitute a violation of the anti-discrimination provision of the Immigration and Nationality Act. You may not require an employee, once hired, to use Self Check or myE-Verify. Use E-Verify to confirm a new employee’s work authorization."

[1] https://www.e-verify.gov/mye-verify/self-check/employers