I don’t understand what exactly did this guy do wrong. He simply observed and chatted with someone and reported what he saw. When someone asked to leave, he left. What’s the problem here exactly?
Walking onto a set without permission is inconsiderate and disruptive because the crew is working very, very hard to make something happen and his presence isn't helpful. He effectively got lucky that he didn't mess something up and accidentally force the crew to work longer and harder than they have to. There's a reason the entire job of some production assistants is just to keep random people off set.
The title kinda makes it sound like he tricked someone to let him on a set, but if you read the story he was watching from a distance and then they started setting up where he was standing. He just stood still until he was asked to move. He employed the same "social engineering" tactics as a frightened hare.
> He effectively got lucky that he didn't mess something up and accidentally force the crew to work longer and harder than they have to.
You got that backwards. It's the film crew that got lucky, since they apparently didn't provide any indication that he shouldn't be in a place he is otherwise allowed to be.