For example in Estonia, every citizen has an ID card, and every ID card is an ISO-7816 smartcard. So they can have this nationwide. Then again, that's a country

For example in Estonia, every citizen has an ID card, and every ID card is an ISO-7816 smartcard. So they can have this nationwide. Then again, that's a country of 1.3M, and you only get the card when you're 15yo. Foreign visitors obviously don't have one. These examples illustrate rather the near impossibility to implement this kind of a scheme successfully, even when backed by a state.