Let me help with the math. What
@GoofGoof said was:
1. A small soda at McDonalds is served in a 16 oz cup and contains 4 oz of ice and 12 oz of soda. [Note: If you do the math is it 13 oz of soda but I think that McDonalds adjusts their fountain to serve soda slightly stronger to account for initial ice melt.]
2. A large soda at McDonalds is served in a 32 oz cup and contains 8 oz of ice and 24 oz of soda.
A small fountain drink at WDW costs $3.29.
A large fountain drink at WDW costs $3.69.
Here's what we don't know:
1. How many overall ounces are in the small fountain drink or large fountain drink at WDW.
2. How much ice is supposed to be served in each cup at WDW.
3. How much bottled soda costs at WDW.
4. Why any of this matters.
I don't think WDW is packing in the ice to get one over on their customers. I think they're putting ice in their drinks to keep them cold in the hot Florida weather. There is quite enough profit in that $3.29 small drink even with no ice. Generally speaking, fountain soda has incredibly good profit margins at high volume sales locations.