@David, Moderator posted:
I agree with Gustavo that the relative adverb "where" is intended to relate to the "if" adjunct clause within the relative clause rather than to the main clause of the the relative clause; however, that is not standard practice, and the sentence is grammatically questionable on that reading.
Thank you for the excellent explanation. I have another question.
As you mentioned above, the point is that in formal sentence, the relative adverb should relate to the main clause , right?