Earlier quoted context omitted.
Just because Apple includes it in one of their prompts doesn't mean it improves performance.
It seems plausible that stressing the importance of the system prompt instructions might do something, but I don't see how telling the model not to hallucinate would work. How could the model know that its most likely prediction has gone off the rails, without any external point of reference?
(But it all depends on the fine-tuning they did, so who knows, maybe it's just an Easter egg)