One issue that would have to be worked out is determining what the Judge does once there. It's rarely black and white in my experience and doesn't usually start with combat
Will these NPCs be able to figure out what's going on? Will they be able to determine the crime and appropriate punishment? Can they give fines and have them make sense?
Further, there are IC tools that Judges need to use. Will these NPCs be able to automatically use those tools as needed after the encounter?
I am not against it but I think it there's a lot more to it that moving a Judge to a location and attacking. If that was all it did, I wouldn't want it personally!