Where I work you're supposed to charge for hot drink/fountain drink cups even if they're empty or just have water or ice. (We have free cups for these purposes, if people would only bother to ask for them.) I'll diligently charge for any cup I see, “assuming they know”. I make an exception if someone's double-cupped their hot drink...unless they're rude. Then they get charged for that shit. A single coffee for $3.85? Yup, guess you should've been nicer, bitch.