They'll be happy to . Just order a Diet Coke with lime. In fact, if you use the same bartender very often, they'll remember what you like.
I've never bought the soda card. Like you, I've heard that the fountain DC can be flat. I prefer to buy mine by the can, but if you drink a LOT of DC it might be worth trying the card. If it seems flat at one bar, try another.
Have a wonderful cruise!
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Thanks for responding Fern! I do drink Diet Coke in copious amounts - will probably do the card. Is it really different in different locations on the ship? It wasn't on Royal Caribbean when we were in the Mediterranean - it was consistent throughout the ship, but tasted a lot different than here in the States. I'll try different bars until I hopefully get the right mix!
Thanks again all of you who help those of us with only 30 cruise days under our belts!!