[ezfe]

While I have no problem with the tag, your claim is false:

> Without the tag there is no way to enforce that without the police having to manually enter the plate number for every vehicle they see.

Police have automatic systems that scan vehicles. I was pulled over once due to an inconsistency in my vehicle registration data (not anything visible on the plate/exterior) because the computer in the police vehicle flagged my car and they decided to follow up on it.

In my case, it was just a quirk of the vehicle owner being unlicensed to drive and there was no violation - but the system correlated the DMV registration details and license status of the owner and flagged the car.

[fps]

fast accurate plate scanners are relatively new. At most, only on police cars for the past 10 or so years. Many police cars still don't have them, only dedicated highway patrol cars. The sticker system has been in place for over 80 years. Systems that work, that are are generally not difficult to implement stick around past when they're technologically outdated.