After 9/11 it was revealed that Muslims already had a way (on a much smaller scale) of doing business across borders without much scrutiny; imagine that in the basement of a Quik-E-Mart or gas station in the US there is a similar set of cubbies in the wall, and when your cousin buys something from my cousin “over there” the “banker” take cash/gold/whatever worth the equivalent from the cubby marked “bert” and move it to mine.
Yes.....
In the very same manner, remittances to mexico can be transmitted via e mail. Two brothers with some money can easily and profitably set up shop.
There is an outcry about taxing the remittances but such a system(s) operating on fairly small scale can easily avoid such taxes.
I am almost certain such a system was conducted locally by fax back when. It was from a restaurant. Interestingly, they also allowed playing the lottery in Mexico from Tennessee by fax. The workers came in on payday and bought tickets. The owner sent the fax and got a ticket number by return.