[eseehausen]

Honestly, when somebody who isn't a subordinate, friend, or direct charge acts like a jerk, I don't think it's worth taking this kind of pedagogical role with regard to etiquette (probably not a good idea in the friends case a lot of time as well). If somebody wants to be a jerk, there are enough providers of goods and services that they'll find one that responds favorably to that. Not to mention that they'll probably rationalize turning them away as the provider being a jerk rather than learning something from it. As DarkTree points out, the provider's response to that behavior is more about managing the provider's quality of life than about shaping customers for the greater good.