I refer to the massive porous borders of the US and Canada and Mexico as "open" borders. I refer to the term "open" as any area in which illegals can cross freely without the proper documentation. I referred to my backyard in AZ as an "open border" as illegals ran past circumventing legal entry. BTW, many of those illegals were "OTM".
Then why do hundreds die each year trying to cross? Why do they pay coyotes thousands of dollars to get them across the border? Why are we spending billions to prevent them from crossing? Why do we have patrol aircraft, helicopters, drones, fences, towers with cameras, patrol boats, movement sensors, undercover agents, rewards, infrared optics, mounted patrols, all terrain vehicles...
You may want more resources devoted to keeping cheap labor out of America, others of us have different priorities for our tax dollars.
Only 5% of shipping containers are searched because we don't have the man power to search more of them. As between spending money to keep Mexicans with weed whackers from crossing the border and keeping nuclear WMDs from entering the country, I opt for more ship inspectors.