While the Trump administration implements its plan to drastically increase workplace site inspections, some states and cities have been pushing back (much like they've done on other fronts). Some have focused on local police actions, but California, for example, recently enacted a law prohibiting employers from voluntarily consenting to certain searches at worksites.
Moreover, retaliating against workers for exercising their employment rights remains illegal — regardless of their immigration status. Employers are prohibited from taking adverse employment actions against workers for reporting safety or wage and hour violations, for example. Courts haven't shied away from awarding unpaid wages to aggrieved undocumented workers either; failing to do so would encourage employers to underpay those who aren't authorized to work in the U.S., they say.
Still, employers must ensure that all employees have completed a Form I-9 and that the form's required documents have been reviewed in person. But they also must be careful not to go too far. Panda Express paid $400,000 last year to resolve allegations that it required too much documentation from immigrant employees.