It's also the preferred route for drug smuggling because the odds of being caught are less. If you seal the land routes, they will just increase usage of the water routes.
In addition to the people entering by land and sea surface routes, you need to add in the number who fly across in small planes. Another favorite method of drug smugglers, the Texas landscape is littered with unmarked private landing fields and private blacktopped "roads".
And since an estimated 50% of illegals currently in the U.S. originally entered legally as tourists, students, business biz etc... and simply didn't go home after their time expired, factor in another unlimited millions.
You simply can't use the same rates for those. It's just plain silly and hyperbolic.
We have to start somewhere, rod. Or, do you want us to become the welfare capital of the world?