We have the Federal Trade Commission for this type of thing. https://www.ftc.gov/news-events/media-resources/truth-advertising
Lots of legal stuff is about parsing word meaning - often to a ridiculous degree.
In this case, I separate Unlimited from Refills. Refills are defined as 10 minutes apart. So when you add the modifier Unlimited, it refers to the count of refills you get … and the time limit between them remains consistent (because Universal has defined a Refill as a unit with a time component).
Is it clearer if they use different terminology? Sure. Our local theme park calls it “all day refills” or something similar.
It’s the same way “All you can eat” buffets are now “all you care to eat*” *within a defined time period. Better to be clear, but makes marketing less catchy 
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