well this would not be allowed here in Germany due to privacy of personal data. For sure it is practical for the state.Many Australian State transport departments have done away with windscreen licence stickers which used show at a glance the month (digits) / current year (colour) for quick visual check of validity/expiry. These days, the "persons in blue" have most of their vehicles fitted with 360 degree cameras with photo-recognition capability which are continually scanning multiple licence plates per second in the following and oncoming traffic... I guess it's the same in most modern cities....