I’m given to understand that a lot of business around the US-Canada border, on both sides, will accept US dollars and Canadian dollars at 1:1 exchange rate.
Do business near the Mexico border operate on the same principle - which is to say, accepting pesos or dollars (though the 1:1 exchange rate wouldn’t work out, obviously)?
Further, do governments have any say on how their money is spent outside of their borders? Could a major American retailer (say, Wal-Mart) begin accepting British pounds, just for shits & giggles, or would the British government try to put a stop to it?
Further to the further, could a government of an independent nation say “Fuck it. Our currency is worthless; from now on all business is conducted in US Dollars.” Could Washington try to put a stop to it?