Yep. This stems from a failure of our Government to enforce our laws. However, taxing the hell out of cash going south is part of the solution.
Shutting down all Western Union store front would also help a lot.
Every Friday when I go to our bank branch there is a huge line of guys cashing their paychecks. None of them have any kind of a bank account and pay $2.50 to exchange their check for cash. Would expect that if people had to have an account with that bank and if they had to deposit that check and not cash it, it would also eliminate some of the cash going south. BTW, I believe my business bank is now owned by Spain although many of the tellers working there are from Pakistan and India.