One of the incidents that gave rise to this case involved a person who was roughed up by the ICE agents before he was able to show his REAL ID, which, once he gave to the agents, they then confiscated and didn't give back to him.
Kavanaugh actually wrote this line: "If the officers learn that the individual they stopped is a U. S. citizen or otherwise lawfully in the United States, they promptly let the individual go."