was this predictive programming for us, or Robin?

I don't know. Maybe the movie gave the killers the idea, or maybe it was known in Hollywood that Robin did something disobedient and this was the killer's way of letting those members of Hollywood know that it wasn't a suicide and that he was indeed killed for his disobedience, and the same will happen to them if they decide to disobey. Thanks for the rapper info - will remember it.