In a number of genres, from Westerns to Film Noir, the staff behind the counter are often shown cleaning out a mug or glass. Having an animation similar in nature could go a long way in adding to the "just a friendly chat, not a drink" nature of trading, I think. As bartenders on television shows will sometimes relay messages, why not have a dialogue option where commanders could ask "What's the word lately?", and they could say nothing new, but they could ask around, which might later lead to the "Mysterious Stranger" message aboard a ship at a later interval.