When the helicopter drops the cigarettes on the town, you see the same helicopter drop three loads. There is no way the pilot could have set down and reloaded twice so fast. If you look at the bottom of the helicopter you will notice it has the same "N" number in all three drops.
Bishop Manley calls Dearborn, Michigan "General Motors country." Actually, Dearborn is the home of Ford Motor Company, its world headquarters and its flagship River Rouge plant. No GM facilities have been located in Dearborn.
When the big clock in the town square strikes midnight at the end of the movie, you can clearly see that someone has to turn the hands manually. The tower is actually located in the opera house and never had a clock in the top set of windows. Those were probably to give more light in the room.
When Amos starts his no smoking patrol he is located on a gravel road leading into town. Why didn't they ever show any other roads leading into town with the no smoking patrol on them if they were trying prevent tobacco products from entering Eagle Rock?
While the whole town does sign the 30-day non-smoking pledge, unless there was a wall around the town to shut people in, nothing prevents people from traveling to other nearby towns and smoking there, then returning to Eagle Rock.