[ponector]

>> You have to carry your passport (or a certified copy of it) along with your visa everywhere in case you are stopped by law enforcement - otherwise, out you go

You have to carry passport everywhere only in police states like USA or Russia.

[sparrish]

That's simply not true.

I've lived and worked in countries in South America and Africa and if, as a foreigner, you are stopped (which happened randomly on roads and in cities) and don't have your papers, you could be deported. It was recommended by the US State department to carry a certified copy of my passport and visa information.