It's happened quite a few times. It's just lazy. This happens most often when they have pre-poured drinks like champagne and orange juice. So when I ask for something different, they are too lazy to go back and get it or try to remember what I want. However, sometimes it happens when they just come to me with nothing in hand. I often sit in row 1 or 9 so it's not like they have to walk back very far. Sometimes, they see me kind of hesitate while I am thinking about whether or not I accept their response and they'll say "would you prefer it in a glass?"
It's only happened once or twice during the actual drink service. The water is right there on the cart so I don't know how much more lazy you can get.
Though, ever since pre-ordering started, I'd say more than 50% of the time, they don't even come by to confirm I still want what I pre-ordered or to even say hello and thank me for being 1K.

That's one of the reasons I don't like 1F. They stick stuff up there so I can't stick my own stuff up there (ie. blankets, pillows, etc). Or they make me move my stuff so they can put their stuff. They usually don't mind for 1A/L