I'd put a "dangerous bend" symbol in front of the "dangerous bend" symbol itself - for authors: It's such an interesting and unusual tool that authors who have

I'd put a "dangerous bend" symbol in front of the "dangerous bend" symbol itself - for authors: It's such an interesting and unusual tool that authors who have it in their arsenal will want to use it, even if just to show off some interesting bit of typography in their book and possibly interrupt the monotonicity of an otherwise very strict formal textbook. But this means that the symbol can excuse, or even incentivize writing exactly such "dangerous bend" passages instead of e.g. structuring the argument or the learning order differently, so the thinking trap doesn't occur in the first place. I think it' a very useful didactic technique to show common misconceptions of something, or popular simplistic but wrong interpretations of a concept. But then it's important to explain what exactly the misconception is and why it is wrong, and not just put a "beware, here be misconceptions" sign next to the introduction of the concept.