Alright, well I'll admit that that is a more reputable source, but that doesn't neccessarily prove that it's true.  I wouldn't be so doubtful of this idea if I had ever heard even a single instance of this use.  Have you ever actually heard anyone use the word "Coke" in this instance???  I'm sorry to be so persistent about this, but I just don't understand how this can be an established fact about the common use of a word in the South when I actually live in the South and have never heard of it. (by the original poster of topic)