ICE will (and already are to an extent) come after anyone who looks like trouble. If they want to superficially follow the law, they beat people up and release

ICE will (and already are to an extent) come after anyone who looks like trouble. If they want to superficially follow the law, they beat people up and release them after 23 hours after "discovering" the person is a citizen. Then, repeat as many times as necessary. Since nobody actually knows who ICE is, it can devolve pretty easily from there. The most pedestrian would be protection money to avoid detention, from citizens and non-citizens, it doesn't matter.