In fact, lst time they did this to me, I complained and it was taken off the bill. I accepted graciously, but pointed out that with th ehigh cost and small size of their sodas, I would not be eating there again without comp re-fills.
In fact there’s a great Pizza place in downtown San Jose with this exact problem (Xxxx House of Pizza) They serve unusual, tasty, thick pizza, but rather spicy. A "soda’ is about a 12 oz serving for I think 1.29 with no free refills. I have told the Mgt that I really enjoy their excellent pizza, but without reasonable priced soda to wash it down, I won’t eat there. They seem confused about the concept of free refills. It’s family owned and very old fashioned. So I don’t go there anymore.
It must be a US thing, because I tend to assume that there’s NO free refills on soft drinks unless it’s specifically stated (either on the menu or on the postmix machine).
I’m not aware of many places here at all that habitually offer free refills on soft drink, except a couple of the fast-food places (and only a handful of individual stores), and some of the American-style chain restaurants (Sizzler does, IIRC).
I, too, had never even considered the whole free refill thing until i moved here. I rarely drink fountain soda, so it hardly ever applies to me anyway, but many places that serve it offer free refills.
Unfortunately, the one place where i do drink fountain soda is also a place where the whole free refills thing doesn’t seem to apply—at the baseball.