Sheriff Joe isn't TECHNICALLY breaking the law. He pulls them over for a minor infraction. So the questions regarding breaking a law to enforce the law are irrelevant to the topic. That's why he isn't in jail. It's shady as heck. It's about the same as asking someone to open their trunk when you catch them speeding. Then you find they have a trunk full of cocaine. That's why it's ok Achilles. How he's going about it is very shady though. I don't agree with his tactics. Honestly, I think it would be just fine to check the legal status of all persons pulled over. Much like the warrant check they do every time you get a ticket.
"I would rather be exposed to the inconveniences attending too much liberty than to those attending too small a degree of it." Thomas Jefferson