Bought one and was careful to order two drinks seperately as they only served one at a time for the card and I was worried that they might say something and embarrass me.
We just purchased the one card but didn't purchase 2 drinks at the same time (husband mostly had alcoholic drinks) both used the soda card thoug.
Yes just get the one, and go back a bit later or go to another bar. The staff dont check the names on the card so you can swap the card discreetly.
One card will do you both,normally give 2 drinks at a time,I buy it all the time for wife and I
Nice for using at dinner table als.
I found that We could buy drinks in a glass for both of us just by showing the soda card permit, saved us running around collecting one drink at one place then another for my husband on a different deck. (tip) keep a bottle in the fridge and fill it on every return to your cabin for in room drinks.