Well make them legal since that is what they want right? A microchip placed in a certain way would keep the Immigrant honest until he/she becomes a US Citizen. How badly do you really want to become a Citizen. Of course they are told after the quick surgery that the microchip was successfully placed inside your body. Tell them we hope you truly understand to report on such and such date or else. Let them wonder what may happen. Of course no microchip was actually implanted but hell he/she doesn't know. There again just maybe you could activate it and Kaboom!