I think the premise is off. DHS said some detainees were on the Visa Waiver Program, which only permits business visits and forbids employment. Others were on B-1, which covers meetings or limited training but not factory construction. DHS also mentioned expired or improper visas. We do not have a full manifest, so some roles may have been lawful, but the evidence presented so far shows that at least some of those detained were not following the rules of their visa.