Aguila Blanca .......Ever sit down in a restaurant that serves Pepsi products and ask for a "Diet Coke"? At least in this corner of the universe, the waitperson is always VERY careful to say, "We don't have Coca Cola here, is a Diet Pepsi okay?"
And generally it is okay. Who cares, cola is cola, right? But I asked once, MANY years ago, why a waitress was so careful to point out that I'd be getting a Diet Pepsi rather than a Diet Coke. She explained that Coca Cola has mystery shoppers who do nothing other than seek out restaurants who serve Pepsi products and don't make that clear if a customer orders a "Coke."
It's less likely fear of "mystery shoppers" and more likely customers like me that can tell the difference........Coke is the real thing, Pepsi is for Yankees.
(Don't put a Pepsi in front of me.)
That was many years ago, and I don't know if the explanation was true even then but it made sense. And I noticed just yesterday that a waitress carefully pointed out when my wife asked for a Diet Coke that "We don't have Diet Coke, is Diet Pepsi okay?" Coca Cola has to do that, otherwise "Coke" will become a generic description, just as happened with Kleenex and Xerox.
"Coke" has been a generic term for a carbonated soft drink in the South for decades..........typically it goes something like this:
Waitress: What you want to drink, hon?
Customer: I'll have a coke.
Waitress: What kind?
Sadly, in the larger metropolitan areas the influx of carpetbaggers has lessend the likelyhood of the conversation above.