Comment by pavon

> This isn't even a coding error, NULL is apparently valid license plate, and for some reason there is a private processing center typing it in to the government system.

I would take that with a grain of salt. The linked article on a talk-radio site, and was likely intended as a wacky news bite that the hosts breeze through and then make jokes about. I figured the exact technical details of what is causing the problem was lost in translation. More likely that they were leaving the plate blank, and then the backend software was confusing null database fields with the string "NULL".