From duck duck go search engine:
The U.S. border zone, particularly the 100-mile border enforcement zone, allows Customs and Border Protection (CBP) agents to conduct searches and detain individuals without a warrant or probable cause. This zone encompasses a significant portion of the U.S. population and includes major cities, where federal agents have broader authority compared to other law enforcement agencies.
https://www.aclu.org/know-your-rights/border-zone] Check out the map and wake up to the fact that this zone has been in effect for many MANY years.
The Fourth Amendment of the U.S. Constitution protects people from random and arbitrary stops and searches. Although the federal government claims the power to conduct certain kinds of warrantless stops within 100 miles of the U.S. border, important Fourth Amendment protections still apply. This helps you understand your rights within the 100-mile border zone.
Here in AZ, we have been dealing with Border Patrol Checkpoints, miles north of the Mexican border, for decades now. I can't get to Tucson for shopping or medical care without going thru one.
Most of the nation has no idea and yet most US citizens live within the zone and can be subject to road blocks/checks.