The real world use cases for LLM poisoning is to attack places where those models are used via API on the backend, for data classification and fuzzy logic tasks (like a security incident prioritization in a SOC environment). There are no thumbs down buttons in the API and usually there's the opposite – promise of not using the customer data for training purposes.
The question was where should users draw the line? Producing gibberish text is extremely noticeable and therefore not really a useful poisoning attack instead the goal is something less noticeable.
Meanwhile essentially 100% of lengthy LLM responses contain errors, so reporting any error is essentially the same thing as doing nothing.
Internal audit teams, CI, other models. There are probably lots of systems and muscles we'll develop for this.