While voluntary I-9 audits are not required by law, they are highly recommended. This is because there are many opportunities to be out of compliance (signing in the wrong box, completing late, not completing all sections relating to ID, etc.), and the fines from an ICE (U.S. Immigration and Customs Enforcement) audit range from $110 to $1,100 per violation and can result in criminal charges and up to $16,000 in fines per each undocumented worker.