As a non-drinker I have run into this and they will not sell the mug without the pour of whatever signature drink belongs in it. They will not do it, even if you pay. I wanted a Nautilus really badly (this was at WDW) and would have gladly paid full price for the drink, but they said they had to pour it. He said I don't have to drink it, but they have to serve it. They could not substitute. I assume this has something to do with keeping the inventory squared away. Anyway, I told the waiter to ask a table across the way if they wanted to drink a Nautilus for me. They did. They waved me over and we had a fun night. I got my Nautilus to take home. In DL, I bought a drink for the person next to me. Still, they had to pour it.
Anyway, one of the mocktails comes in a pretty cool sipper, though it is plastic. I just want everyone to know that they are pretty strict about this.