Dealing with the public:
I am not of the opinion that the customer is always right. I always go out of my way to deal openly and honestly with customers, but if they behave unreasonably or are just plain wrong, then I don't care who they are, and if that loses me some customers in the long run, that's just tough beans.
There is, unfortunately, a big difference between dealing with customers of your own organization, and with customers of a company you work for.
There is this unfortunate attitude with some of the public where, when they don't get what they want in the way that they want, they feel justified in making the person they are dealing with (a.k.a. Jason, or myself at the cash register) the object of their vilification. It takes practice to develop a thick "skin" of outward projection, so that their rudeness simply rolls off. When faced with these situations, I simply remind myself that they are really venting against the situation, and not against myself personally. I then focus on the next customer, who is usually a true charmer, grateful for every assistance I can give.
The true villian in the scenario that Jason has given us is his supervisor, who has not learned how to roll with the punches. Instead, said supervisor has decided to make Jason the villian (as if he could ever be one!), and written an e-mail to his own supervisor targeting Jason.
This is reprehensible behavior, as far as I am concerned. Jason is right to be outraged.
The best response would be for Jason to write an e-mail in response, to the uber-supervisor, explaining his actions in as non-emotional language as he can. If I were Jason, I would not even mention his direct supervisor, except to explain that he was taking the initiative to stop an inflamitory situation early, rather than let it continue further and disrupt the corporate structure. I would appologize for any impropriety the action I'd taken, and ask for advice as to what action should be taken, should the situation arise at a later date.
In other words, I would remain a cool, cool, considerate man. And I'd leave it to the ubersupervisor to decide what action needed to be taken next.
(By the way, I've been there, done that. I had a supervisor who wanted me fired for her own incompetence. I was able to get transferred to another department, after having a conversation with our ubersupervisor. The supervisor who had been my nemisis then got fired, when it became clear that she was the cause of the problems. About two years later, der B and I ran into her again...outside a gay nightclub. She was entering, we were exiting. She immediately tried to pump me for information about what was happening at the company, buddy-buddying me about how we gay people should cling together, about how our uberboss was homophobic, and how she was sueing the company for wrongful, discriminatory termination. I wasn't buying. I'd been out of the closet for years, she'd hidden, and I was the one who was still around. I managed to skitter away from her clutches, and reported the conversation to the powers that be. It's the only time I've ever purposely outed anyone, and I don't feel sorry about it one bit.)