Other mistake: As Mrs. Threadgood is recounting the illness of Ruth, she mentions that Ruth was moved downstairs in the house. In fact, Ruth is actually in bed in an upstairs bedroom.
Suggested correction: The scene was moved downstairs after Jon Avnett (the director) thought how he wanted to shoot Ruth's death. He wanted Idgie to be looking out of the window, not actually seeing Ruth when she's passes. Jon thought that they would have moved Ruth downstairs where it was easier to take care of her instead of going up and down the stairs. So Ruth actually died in the living room of the house that was turned into her makeshift bedroom.