Stuart,
You are most likely correct as usual but here in the South we do and say things a little differently. When someone ask if you want a 'coke', they don't mean a "Coke-a-Cola". Other places call them dope, soda, pop, or whatever, we just refer to all of them as cokes. Same with facial tissue, we refer to all of it as "Kleenex". Now, where's my cup of 'black joe'? Thanks for the 'heads-up'.