It is 2018, so it would be realistic to think that robots would be existing in this day and age and they are. 

In a report done by CBS News in NYC, the robots are currently deployed in Airports and select parts of the Tri-State Area and they are used to develop imaging and information in their surroundings that would be useful for the security team.  Here's what these things can do:

Each robot has five cameras, four of which help the robot see things. The other is used to get thermal imaging data. All of the information gathered goes to an internet-based portal that helps local security forces on the ground.

“The law enforcement apparatus is not going to scale,” Li said. “You can’t keep adding more people, and we’re going to add more people and more officers. It’s not going to happen. Society literally can’t afford this.”

The robots are able to observe people walking on the sidewalks, record license plate numbers, detect the heat in objects, and see which cellphone serial numbers are within a designated patrolling area.

Knightscope said the data is secured and is only seen by the security agency controlling the robot. They’re able to stop it and tell it what to look for, but it doesn’t have a joystick that would allow it to follow or target a specific person.

It is New York though, so I'm curious to see what would happen if someone hit it with a bat, or poured liquid on it. If that happens, does the drone-like robot defend itself? Or does an alarm go off? Those scenarios aren't listed in this article.

This program is about to be rolled out to 16 cities so we shall see what happens before it gets to North Dakota.