It's just such a great example of how people could react either with uproarious laughter or by feeling that some boundary has been violated and can think that either reaction was the most self-evidently obvious one in the world and the reasons for it were entirely contingent. It's something where you can only really witness the irrationality of it if you're in the author's position.
I once heard it speculated that philosophy might have emerged in Greece because the circumstances of being merchants engaging in interstate trade, you could see the way that certain things regarded as received knowledge were really customs, peculiar to certain cultures and locations. When you're the prankster and you can see different people reacting in different ways that seem to be tied to patterns of the circumstances of how they experienced it, you can kind of witness the contingency of those reactions playing out in real time.
FTA,
> Having sent this out, I fielded a few anxious calls, who laughed uproariously when they realized, and I reset their printers manually afterwards. The people who knew me, knew I was a practical joker, took note of the date, and sent approving replies.
I doubt a single person "laughed uproariously". Most often they probably rolled their eyes and gave a sympathy chuckle. The people who knew he was a "practical joker" understood how much of this guy's ego was tied to his inaner sense of humor and laughed along to get out of the conversation with him.