Well, what I was trying to get at was that simple mention of fluid/soulstone trade seems like it'd be bait enough, but the way it was written took it to ridiculous extremes beyond my ability to swallow, with constant harping on what they're doing is illegal.
If I saw a cup game coming up on the sidewalk and I walked by two men loudly discussing how to beat the cup game, I would not think "golly, now I can go win some money!" I would think "associates trying to round up marks". The fact the guardsman opted to follow them even after reflecting on how ridiculous the conversation was, makes him an idiot rather than a tragic figure.
EDIT: To be clear, I don't dispute the "bait" nature of the conversation. I'm saying that the way the conversation as currently written is extremely obvious and poor bait, and doesn't serve the rest of the story (which I liked) well.