I'd actually flag as very low quality here.
Such answers have no salvageable content and should be removed. I would also leave a comment explaining why the answer is unusable and dangerous and should be deleted.:
Warning: The steps in this answer will delete all data on your system and may brick it altogether. As this answer contains no salvageable content, I've flagged it as very low quality.
An actual attempt to answer the question, even if incorrect, does not merit a flag. However, this is not a genuine attempt to answer the question; instead, it's an attempt to mislead the question author and other readers.