Yes, I've noticed that also. License plates on vehicles in television shows and movies almost always have an invalid number. For example, if a state uses a three-letter-three-number scheme (ABC123), the prop license plates may use a three-number-three-letter scheme (123ABC).
The problem described in that blog post is unique to California. Where I live, license plates stay with the owner. If I sell my car, I keep the plates and put them on the next car I buy. In California, the license plates stay with the car, even if the car is sold. In addition, California does not re-issue license plates when the style changes. As a result, cars in Californa have can have many different styles of license plate. For example, a car registered in California in 1966 would be issued a yellow-on-black six-character license plate (ABC123). If the car stayed in California, and the registration was kept current, it would keep the same license plates. If the car is sold in California, it would still maintain the same license plate.
As a result, a person can tell (usually within a few months) the date a vehicle was registered in California based on the license plate number. Of course, it does not include vanity/personalized license plates.
I made a reply to that blog post, and it reads as follows:
They are all prop license plates. The fact that new cars have old license plate numbers isn't the only problem with them. According to
http://www.dmv.ca.gov/pubs/plates/standardplates.htm, the California Department of Motor Vehicles does not use the letter I, O, or Q as the first or third letter in the three-letter sequence. As a result, those license plate numbers are invalid and would have never been issued by the CA DMV.
In addition the CA DMV does not use many other three-letter combinations. A California license plate collector has a list of unused three-letter combinations on his website
http://www.calpl8s.com/cpinfo.html.
I should also add that the 2QRI445 license plate is the incorrect style (known to license plate collectors as a "base"). The "Script" base (also known as the "Lipstick" base) was first issued in 1996 with number 3GAA000. If the 2QRI445 number was correct, it would have been issued on the previous "Embossed" base used since the "Golden State" base was eliminated in late-1987.
It is pretty common to see prop license plates that are the current "Script" base but have a 2- or 3-series license plate number that would have been on a different base.
The most famous fictional California license plate is probably 2GAT123. There's a Wikipedia page for it at
http://en.wikipedia.org/wiki/2GAT123. It would have been issued on a "Golden State" base.
I would like to add that commercial vehicle plates with the 1A12345-style are not simply issued based on use. You would not be able to drive a Peterbilt with a 1ABC123-style plate. In California, commercial vehicle license plates are not simply issued based on use, but also based on vehicle weight.
You can find more information about California license plates at these websites:
http://www.calpl8s.com/
http://www.15q.net/ca.html
http://www.dmv.ca.gov/
http://en.wikipedia.org/wiki/Vehicle_registration_plates_of_California
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