So I came across this just now:
(Note the timestamp above)
It was on this question when I saw it:
Represent JSON Array into String
That said, this ad was taken down a while ago.
I consider it a bug that it's still being shown.
Note, this is in no way about my opinion on the matter (I have none, really), it's about an obvious contradiction (hence being tagged bug).
A => B
,B' => A'
type situations?