It means they keep a really tight lid on things...visible presence, enforcing early closings, lots of pretextual stopping of cars for very minor things like turning into the wrong lane but they're really fishing for DUIs, etc. It's what happens when church groups can run the city government, or a sheriff is convinced there's a crime epidemic and he's got to stop it. They're just two steps from prohibition and one from being totally dry.

Towns like that are known for kids trying to get out (college if affordable, Army for last resort) and then not coming back except to visit parents on holidays. If you really train your eyes and ears you can pick up the vibe.