When I go through Immigration, either in the U.S. or a foreign country, they take my passport and scan it like a credit card. Then the officer stares at a computer screen. What information is the officer looking at and how detailed is it? How much is shared between countries? If I’ve visited more than one other country will it show up due to a uniform shared database? When they stamp the passport there us usually hardly any ink in the stamp pad so I assume that is merely a formality for the purpose of tracking people.
I have an older passport, issued before the US started putting chips with more data in passports. When traveling recently, I’ve gotten several good looks at the screens of immigration officials (never in the US - their screens always face away), and it looks like the information that pops up is the same as the info on the inside front cover of the passport - my name, DOB, passport number, etc.
I think the stamp in your passport is used to easily check on you if you’re detained within the country to see if you’re there legally, since it’s always got at least a semi-legible date on it by which you need to leave the country. However, I’ve never been detained (which is totally OK with me), so I’m not entirely sure about that.
Can’t answer all your questions, but here’s what I know:
Firstly, I presume we’re talking about an MRP (machine readable passport). Those are the kind with the lines of characters at the bottom of the picture page. I can say for sure that the immigration officer will see details of any previous admissions to the country you visit, and in most cases, any problems you’ve had in the past. For example, my wife recently entered the UK (she’s a US citizen) and the officer could see that she had been denied entry to the UK in June 2003. Actually, he was pretty kind and said he would remove that from her record now that she is here with a settlement visa.
Presumably they also have some details about some types of arrest warrants and the like, but I’ve never tried entering a country where there’s a warrant on me My life just isn’t that exciting.
I have no idea if countries share this information as a general rule. I believe that US and Canadian border agencies share some data, but I have no cite for that at the moment.
The passport stamps are there for various reasons. I think the main one is to inform the traveller of any restrictions on their stay, so that no-one can try pulling the “Well I was never told I had to leave in a week!” type argument. They might also be useful for LEOs who don’t have access to the immigration computer systems, I don’t know. For some reason, the stamp placed in my wife’s passport is important when she later applies for permament residency a couple of years down the line. I suppose it proves that she entered legally and was inspected by an immigration officer, though I would have thought that information would be on their computers.
My passport is never stamped when entering Canada. I’d say it’s only stamped about 50% of the time when entering Mexico, although (a) when I was there on an FM-3 (work/resident visa), it was stamped 100% of the time, and (b) on a passport alone, they give you an immigration document that you must retain and surrender upon leaving the country, which I’m guessing serves as a stamp.
I think it depends which country you’re a citizen of and where you’re coming from. My passport is never stamped entering the UK or any other EU country (I’m a UK citizen) but always when entering the USA or Canada. My wife always gets a passport stamp when she enters the UK.
In the US, non-citizens (except Canadians) have a document like the one you mention. It’s called the I-94 or I-94W. It’s stapled into your passport by the CBP officer when you arrive, and then stamped with your admission date and port of entry. Airline staff (or Canadian border guards if you leave by land into Canada) collect it when you depart.
the Guardian had a pretty detailed article on the new passports. A brief overview:
The point is to help prove that the passport is authentic, because the date in the chip matches the data printed on the page. However, there’s ample evidence to suggest that this only deters low-tech forgers, and hasn’t really addressed the more significant issue of fraudulent (but authentic) passports.
Of course, the huge red flag raised by the 9-11 report was that the passports aren’t tied to meaningful data. At least six of the hijackers were travelling under their own passports and there was nothing in place to connect their passport to their name on a terrorist watchlist. (but i digress…)
My life just isn’t that exciting.