Why not just give away 32 oz. cups. If the customer decides to pour both of their 16 oz. drinks into it it's not your fault.
KC
That would work, too, but then you'd have 3 cups per 32 ounce soda sale, instead of one (for the 32 oz size) or two (for the Bloomberg Special- 2 16 ouncers).
It would increase overhead.