Thanks from your response, in fact I want to know what if for example GBP had the situation of Dollar? Now for example USA buys a good from country x to 1b$, can it simply print the dollar and pays the debt to country easily when in treasury there is not any money? I hope I can explain what passes in my mind.
They have already done so. They even went so far as to sponsor so-called freedom fighters all over the globe with the newly printed "authentic" US dollars (starting from the Soviet-Afghan war in the 1980s). Needless to say, that these dollars are forbidden to enter the territory of the US...
I have never heard of these type of US dollars, can you provide a link or citation?
These are essentially the same dollars, but their serial number ranges are being tracked (on the pretext of them getting into the wrong hands). Actually,
this is no longer a secret...
That link is about bank wires only correct?
That should be about Terrorist Finance Tracking Program. An interesting quote from there:
2012, February 26: Danish newspaper Berlingske reported that U.S. authorities evidently have sufficient control over SWIFT to seize money being transferred between two EU countries (Denmark and Germany), since they have seized around $26,000 which were being transferred from a Danish to a German bank. The money was a payment by a Danish businessman for a batch of Cuban cigars previously imported to Germany by a German supplier. As justification for the seizure, the U.S. Treasury has stated that the Danish businessman has violated the United States embargo against Cuba
As you can see, they don't even care about the money entering the jurisdiction of the US. If you asked about cash flow, you can rest assured cash is being tracked too...