I lived in Yuma. The border patrol could stop anybody for no reason all and ask for “papers”. Along Interstate 8 there are check points, they will question you and if necessary search for car. Now if the State of AZ does it with just cause, It’s called Racism?
All the border states have checkpoints sometimes thirty miles from the border. We've visited Big Bend National Park several times in the last three years, and there's one that's about thirty miles from the park entrance. No problem with being asked for IDs. And we don't look Mexican or Hispanic...however that's supposed to look.