No, what it would do is remove for the most part the incentive that draws them here.
Even if they went back to trying to mail cash all cash can be tracked today through RFID tech and it would then be easy to detect cash being mailed to addresses outside of the US.
If the border is secured to a high degree you can also catch people trying to move money out of the country physically through the legal ports of entry.
There’s nothing we can do that cuts off every avenue in and out of the country for people and contraband but what we can do is make it so expensive and difficult that we reduce the flood to a trickle.
This would also force Mexico, Central, and S. America to deal with their own problems, especially their economic problems.
Remittances, primarily from the US now exceeds their total petroleum production as the largest part of their economy. If we could only cut that by half Mexico would have to make dramatic changes to their economy and to protect their own interests would be forced to get serious about cutting off the flow of illegals from their southern border as well to protect them from economic collapse.
It would also force the countries to their south to either clean up their own acts or face violent revolution as people who can no longer flee are forced to stay and fight to make their countries more like the US.
I doubt many on the left are even aware of it and if they are they simply dismiss it.
I don’t know what the requirements are like now but basically to move to any western European nation back in the 80’s you had to have proof you could support yourself at a middle class level and have a sponsor or in the alternative or have a native sponsor that was 100% responsible for you financially.
My family seriously looked at moving to either Australia or New Zealand back in the 70’s largely because of gun rights issues and because of the opportunities both offered and at the time to emigrate legally to NZ You had to have a minimum of 250k for each adult, and 50k for each child in the bank and move those funds to NZ before you could legally get into the country as anything other than a short term tourism.
what draws some of them here is the opportunity to make more money vs their country, some of them come from the poorest regions of the country and they don’t want to be associated with the cartels.
The mexican peso is weak, making 20 dollars U.S a day can feed their families for a week or two.
As long as the U.S and the IMF keeps giving those countries money , there is no incentive to solve their problems.