Originally Posted by
Bandicoot
Yeah, but... I think the chances are very very great that each immigration agency (in any country, US, UK, India...) has software that pulls in a great deal of information on you from various other databases of immigration and other matters. When they scan your passport, it's not just your DOB and passport number and such that they can see on screen - very likely they can see your full profile with all exits/entries on record, even those connected to other passports and so on, and they can pull in additional information if needed too.
I would imagine at a minimum the agency is also referencing joint databases both internal and those provided by allies (e.g., terror watchlists, Interpol notices, wanted persons databases, criminal records, etc.).