“They cross through Ports of Entry, and claim they are visiting, shopping, ETC. Many cross daily and work in U.S. “
The most popular cable channel in Mexico is just cameras facing the border checkpoints. A running banner saying something like, “Expect 20 minute delay at gate four as vehicles are being hand searched. Gate two has no delay. Dogs are deployed at gate three. All other gates five minutes or less.”
They legally cross, it is legal for them to come across border cities to visit, shop- same as we can do in Mexico. They are not supposed to work here. At busy ports they don’t get recognized by Customs Inspectors (who rotate jobs frequently) for crossing daily, many have family on US side but tons more have jobs.
They are allowed to cross pretty easily and are not supposed to stay or travel away from the border. If they are crossing to travel away from the border they only need a permit.
Children freely cross the border to attend school in the United States daily and return to Mexico at night.
Mexican citizens who do not have a criminal record, have ID, and can show proof of living in Mexico near the border can legally cross. Those denied this- it is usually due to a criminal record either in Mexico, the U.S. or both. It is easy for them to legally cross through ports of entry that is why those crossing the desert, sneaking in are usually criminals.