Rabies tag/certificate and a healthy looking dog gets you down the road (or up the road if your headed north). If your dog looks ill, acts ill, or does something to bring unnecessary attention to its self, then you might get a more thorough inspection.
Remember these border folks see hundreds of dogs every week and have experience recognizing what a normal healthy dog looks and acts like. If they see something from your dog that they determine is abnormal, then more scrutiny is given.
Lakeside