The cities are closed regions, as are the roads connecting them, and they have specific problem spots with lots of guards, or people in your way, etc.. (quanticfoundry.com)
Now the city uses them only for problem spots, athletic fields and a rose garden. (articles.chicagotribune.com)
Sometimes, handlers gather in little groups and discuss potential problem spots and how they are going to handle them. (americanshihtzuclub.org)