The cartels already do that with their drug money. Ask all the interdiction teams set up along I-10. However, the logistics of that don't make sense for Pablo trying to send $100 to his village or whatever. If anything, it's more likely that another Mexican here legally would take his cash and use their bank acct. to Zelle money for them.
That said, we should be screening vehicles in both direction.
If the path into Mexico remains open, people will just drive across the border with their money. Or the cartels will.
That said, we should be screening vehicles in both direction.