It's fascinating how you can continually miss the point. Let's give it one more shot.
They don't try to run across established border crossings because they know they'd be shot. If they knew they'd be shot swimming across the river or climbing a fence they might think a bit before doing that.
Is that clear or do you require further explanation?
You are the one who is dense. The U.S./Mexican border is almost 2000 miles long. We do not have the manpower to watch every linear foot of the border. They know that. They use that for their benefit.
The ones making big bucks charging to help people across are not stupid - they know how to watch for patrols and avoid them. Hell, I'd bet the majority who are helping people cross the border are from the U.S. (assholes) They know the land and, judging by their obvious success rates, know how to use lines of intervisibility, natural (and probably some man made) concealment, etc. That means having some dude watch 50 miles of border through binoculars does not work. We have to PATROL the border, back and forth. And while our border patrol is going forth, they're sneaking in behind. And then there are the tunnels. Do you think those tunnels were dug by people coming in?
We have our patrols out. Their numbers are woefully short of what it takes to do the job even half assed. They were augmented by some military for a while, but Obama has withdrawn those troops. There weren't enough to make a significant difference anyway. To do the job so as to completely shut down the border, we'd need between 16,000 and 20,000 men on the border 24/7. Figuring 40 hr weeks, that's over 85,000 men just for patrols, and not including supervisory staff, support staff, etc. And the logistics of supporting a constant patrol over 2000 miles of border isn't child's play either. We'd need a few regiments of choppers to get people where they need to be and pick up the patrol coming off shift. All this means money - a fucking ton of it - that we do not have.
No, we don't shoot them. (that is asinine beyond contempt. You never did aswer my inquiry either - do you advocate shooting women and children as well?)If people are caught trying to cross, they are arrested and after some processing, trucked back. (only to try again the following week - probably successfully.)
There are, reportedly, some vigilante groups out there willing to do so. But, I haven't heard of any "success" stories, and I would imagine if there were, there would also be some murder-1 and murder-2 charges being filed over it.
All-in-all, though, it is not a job that is anywhere close to as simple as you try to make it out to be. I'd bet you and your best buddy could not even patrol one mile of border and prevent me from crossing it. We're facing almost 2000 miles. And that does not include the possibility (probability) of ocean routes.
The better answer, IMO, is make it so they don't get what they are seeking by crossing illegally. We need new laws in place that criminalize hiring illegal immigrants. Fine the hell out of those who do, with jail time for repeat offenders. Cut off the employment and shut off the government freebies. If there is an anchor child, get them in a decent LEGAL home and send the parents packing. THAT, by itself, would give pause to those who plan on securing their status with a baby. And, if we set conditions so no one will hire them, government services are off limits to them, then they'll have no reason for risking an illegal border crossing in the first place.
At the same time (carrot and stick approach) we open up legal immigration a bit, according to the needs of those who do depend on immigrant labor. Speed the waiting line for legal immigration substantially while making illegal immigration far less attractive, and they'll have even less reason to break the law to get what they want. And the worst action we'd have to take is taking a child away from the parents, with an upside of giving that child a significantly better life than their natural parents could give them as illegal immigrants.
