In the communist state of Russia and East Germany all citizens had to compulsorily carry identification papers with them. It listed their place of work, their place of living. If they were nabbed anywhere away from these two locations, then they could be arrested. Usually the officials accept your reasons, but when they did not, the citizens were send off to concentration camps for ever.
Why am I telling you so?
Indians now have to carry their papers everywhere. Random checks will happen and documents not being in order, is a just reason for arrest.
This is very interesting because a 1/3 of the citizens cannot read and write. So it might be hard for them to know whether they are carrying their papers or their wife/kid’s documents. Also Ration Card (PDS) is the only form of documentation for majority of the citizens, but you cannot get one if you do not have a house or live in slums.