If I'm in the mood for a fight or two, I'll suggest to my Dragonborn that she give the money to the completely trustworthy and innocent looking dark elf who just needs a helping hand. Otherwise, I suggest that she ignore him and go Miraak hunting instead.
My Imperial stopped paying him after awhile because all of the people who were dying. I RPed that he was too honorable to risk additional innocent life.
True, but IRL they're trickier and come off as sincere. At least the successful ones.
BGS games usually "tell" you upfront when something is off by overdoing the acting and dialog. But then I always meta-game it, because I want to see what will happen.