Victoria isn't a city at all, it's a state. But it's the Mildura police that issued this warning. Mildura is certainly a small town.

Without this degenerating into an argument over semantics, by that line of reasoning any police officer would simply be a 'police officer in a small neighbourhood police station' no matter how large the police body is. The warning was issued by Victoria Police members and is on the Victoria Police website, I don't see there being any issue with its credibility.

Mildura has a population over 30,000, so it's not a small town.

There is no problem with the credibility of the article - the problem is with the sensationalist/linkbaiting headline. Most people are going to assume upon reading the title that 'Police' refers to something a bit more substantial than the police force of Mildura, Australia.

They represent the state police force as a whole.