Mostly Harmless, that is not 100% true. Although I agree with you here in Brazil there are lots of N registered business jets that require FAA licenses to fly them and since most Brazilians don't have FAA licenses, it is a good option for those who do have one. I am not sure if other countries are the same way but it is cheaper for the plane to be N registered than to have it registered in Brazil. Lots of red tape and high costs. So in this case even though you could not be able to work in the US, you could fly any N registered aircraft here.
VF