In Florida it is 100% (state law) for most building but there are plenty of places where enforcement is lax. That would basically be the places where you wouldn't have permits if the state didn't have a law. I imagine permits are just a check written to the county without any real inspections in places like that. In real life that means no permit. Fla statute 102.2(C) exempts nonresidential agricultural buildings so as soon as you get out of town everything is a barn.
