How the U.S. border patrol tried to keep the Mexicans out in the crossing by Gary paulsen?

In "Crossing" by Gary Paulsen, the U.S. border patrol deploys various strategies to try to keep illegal Mexican immigrants out, such as setting up checkpoints, increasing patrols, and using technology like drones and sensors. The novel follows the journey of a young boy attempting to cross the border and the challenges he faces in evading these measures.