From Jenny at A Call To Wings, quoting a book she's reading at present:
During World War II, for example, three German submariners escaped from Camp Crossville, Tennessee. Their flight took them to an Appalachian cabin, where they stopped for a drink of water. The mountain granny told them to "git." When they ignored her, she promptly shot them dead. The sheriff came, and scolded her for shooting helpless prisoners. Granny burst into tears, and said that she would not have done it if she had known they were Germans. The exasperated sheriff asked what in "tarnation" she thought she was shooting at. "Why," she replied, "I thought they was Yankees."
Probably figured they were some of them pesky Pennsylvania Dutch Yankees . . .