Most of the seasonal workers who work in fields in the US are content to go back to Mexico after their season is over. A good number has built houses in Mexico and saved some monies because the cost is living is lower. They are not interested in becoming US citizens. I believe they already have work permits every year. This information I got from an article I read maybe, 7 years ago. Those that should not be let in the US are those gang members coming from Latin America and coming here to commit crimes. They know they can get deported after proceedings but, will slip back in the US. Now, with open borders, they will just establish roots permanently, no law enforcement dare arrest them.