[pmontra]

No idea, it's been like that since forever AFAIK. At least it solves a lot of problems (you just show your photo id) and basically everybody you have a contract with would know that information anyway, utilities, banks, etc.

Edit: there is a difference between the place you live and the place you are registered into. Example: a student is registered at parents' home and goes to study at a university in another city. He rents a room there. He has a contract there and the landlord must notify that the student lives there (since the terrorism laws in the 70s) but the student is still registered and votes at the city of his parents unless he registers at the other city.

This is common also for workers. Maybe they live for years in a city (and the state knows) but they are still registered on their home one.