I find it hard to find a link whereby US domestic 
is magically transmitted into international law 
by Credit card companies!  Sounds like 
imperialism to me!!!

Considering the US government has not ratified 
many pieces of international law I find it hard 
to believe that other states will allow these 
credit card companies to install foreign laws in 
their soil!!

Interference in the domestic affairs of another 
state is one of the main tenets of international 
law.  That is why the US has to be careful in 
Afghanistan that it is not seen as bullying 
another state & has just cause in its aims.

And as i already stated plenty of places in the 
UK charge a 3% surcharge for credit card payment!