Ethically do you even have to cite something properly when the person who solved it was intentionally anonymous? If the concern is that people will think the person writing solved it, they can just write a sentence where it came from.
another great example is Bitcoin paper.
Yes. Not because they need/want the credit, but because it's important to note that it's not your idea.
> If the concern is that people will think the person writing solved it, they can just write a sentence where it came from.
That is, basically, what a citation is.