If you're in the eastern parts of the map (which you obviously are) you run the risk of running into raiders when moving about (they used to be spread evenly throughout the map).
If there's a new "controlled territory" fairly close I would assume they've set up a settlement or possibly a war camp there, which probably means they may have an increased level of raider activity where you are.
So, if you want to be safe from Njerps you should move to the western part of the map (but you won't be safe from robbers anywhere). Otherwise you should be prepared to suddenly run into a patrol as well as seeing them at a distance. Once you encounter them you'll have to decide whether to fight or try to flee.