My only concern is that the Cartels' coyotes who get fired upon, if that happens, will escalate the level of conflict. It would be bad optics for the Guard (in the current mass media environment) if the Cartels started using 'migrants' as human shields, and I would suspect that short of all out war on our part, the Cartels have as much small arms sophistication and gadgetry as the troops. This is big business, and the notion that they can't pick over the world's arms markets is folly--they likely are very well funded.
In a nutshell, this would lead to the (possibly necessary) all-out war at the border that would be 'reported' in the global(ist) media with the US (or even just Texas) presented as the rogue aggressor, especially considering the precedent this administration has set with regard to illegal entry.
I understand your concern and you are absolutely correct. However, equal or greater concern should be for the safety of American citizens. Instead we have an invasion, squatting, rapes, murders, etc. Americans have become victims because our country does nothing and those entering know it.
The initial shock of Americans fighting back and defending their border would be huge, but once known, I doubt that will see the magnitude of the invasion that we are seeing now. It is needed. It has gotten to the point of, we either defend our country or we will lose it.
Border wall first, mass deportation, and announcing that the U.S. will no longer tolerate illegal entry. It wouldn't take long for the 'climate' to change.