For what it’s worth, here’s my personal take. I neither have, nor claim, any specialist knowledge of the matter; this is personal opinion only.
Lower down the ladder, for Production people, there can sometimes be an uncomfortable tightrope to walk. Imagine, for example, a scenario in which the star you’ve been tasked with producing behaves repeatedly in a way you consider unacceptable. Supposing, say, he insists on getting his penis out and waving at you, before urinating in a paper cup and offering you the contents. You’re not enjoying this and you go to the boss to complain. In the Human Resources text book, the boss listens sympathetically, investigates and then deals firmly with the miscreant. On planet real-life, there’s no guarantee the boss will do any such thing, and every probability that, if you go in proclaiming that the town ain’t big enough for the both of you, you’ll find yourself on the next outa-town bus to Nowheresville, while Mr Willy Waver moves on to wave his member at your hapless successor.