I had one bartender on my last cruise tell me there was a 15 minute wait time between finishing a drink and ordering another. I ordered a drink- didn't care for it and tried to order another. When I questioned why I had never been told this before he just looked blankly at me. So I said, ok, just let me know when the time is up- you can take the first one away and just let me know when I can order the second.
He decided just to make the second drink with no wait time then.
Honestly, it was weird. It was in the morning- so I had not had too many to drink- it was probably my first drink of the day. We were with a group of people- and I had decided to have the same drink as everyone else vs what I originally ordered.
I didn't go back to that bar the remainder of the cruise because the service was just off there. But I wasn't mad or anything- just thought it was weird to be told it was a rule that wasn't true at all.
I've ordered drinks, shots, etc without any questions at all other bars. It was obvious we weren't sharing- our entire group had the drink package.