SQL Injection via License Plate

The title is "How a 'NULL' License Plate Landed One Hacker in Ticket Hell", covered on HN before at https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que... . (467 comments at https://news.ycombinator.com/item?id=20676904 ).

FWIW, I don't quite think it's an example of SQL injection. That comment links point out similar failures with "NO PLATE", "NO TAGS", and others.