This is comical to me, as anyone who has heard me speak can attest that I have more than a slight Southern drawl and liberally pepper sentences with "y'all".
The crack about calling everything "Coke" is actually true, we do call everything Coke. But if they really wanted to gauge someone's Dixie influences, they should ask questions like:
What do you call a small restaurant establishment that serves breakfast or dinner at any time of day?
If you are designing a city, what would you use as a basis to name the streets?
What do you call the war that occurred in the United States in 1861?