it's kind of like they are made of the same thing.
Me: Excuse me, waiter, I need a new drink. Mine is watered down.
Waiter: You're drinking water, m'am.
Me: And step on it.
Although, you could pour whatever beverage you'll be drinking into an ice tray, freeze them, and use those in the drink. That way when the "ice" melts, your drink isn't diluted. But that obviously takes planning in advance.