From Nogales to Tucson there are a few checks and then onto Phoenix none. Who cares if her passport allows it. They stamped it! I travelled that road many times. I had mining claims all the way to the border! Laxt time, I went and US border said therewas a gunfight 20 feet away the night before!
When they leave US immigration never checked her out! I know, one time she was not let in and I met her at the entry to Mexico. She later came through. Just a minor wait and they allowed her in.