Billions of dollars leaves this country every year from all aspects of life. One way to control the flow is to place a tariff or tax on all transfers over $100. The only way to control illegal immigration is to stop the money flow. If it costs to much it will not be worth it.
If someone is sending thousands of dollars to another country every year we should match it to the tax returns. If they do not match we go after them. (I understand there are already fees but $10,000 is the current limit before you report it)
The money is there we are just to PC to go get it.