In Italy you're meant to always carry a valid, officially accepted form of ID (and as far as I know, only ID card and Password fully qualify, but driving or nautical licenses, gun permits, and some forms of railway employee ID are also generally accepted as they're ultimately made by the government) and it's a crime (with up 2 months in jail, though it's usually just a fine) to refuse to show it upon request to on-duty "public security officials" (Italy has a bunch of entities in addition to the normal police) and in a few other rare categories (a bus or train inspector has the power to demand your ID if you're travelling without a ticket and need to be fined).
If you don't actually refuse, but you explain you just forgot your ID at home, you can still provide your details verbally and are usually allowed to go, and "invited" to show your ID within XX days at any police post. But if you were driving a car, there will be a small fine anyway.
If the officer has any suspicion you lied, or that your ID is fake, you can be taken to a police station for identification.
Additionally having a continually up to date registry of persons would definitely not fly here.