Reinforcing an avoidance tactic is nowhere near as effective as doing that PLUS enforcing a positive tactic. People with loads of 'DONT', 'STOP', etc. in their instructions have no clue what they're doing.
In your own example you have all this huge emphasis on the negatives, and then the positive is a tiny un-emphasized afterthought.
I think you're generally correct, but certainly not definitively, and I worry the advice and tone isn't helpful in this instance with an outcome of this magnitude.
(more loosely: I'm a big proponent of this too, but it's a helluva hot take, how one positively frames "don't blow away the effing repro" isn't intuitive at all)
The trick is to explain why something is important, not just to emphasize it. For instance:
"As an LLM, when Claude used 'sed', it can quickly and easily break files that are difficult for the user to fix. Claude must be aware that an LLM's actions seem effortless to it but to the user it represents hours of work getting things back in order."
In your own example you have all this huge emphasis on the negatives, and then the positive is a tiny un-emphasized afterthought.