I have come across this kind of a past perfect usage a couple of times, and yet, I still don't understand why it is used the way it is. I hope someone can shed some light on it for me.
E.g.
“Just in case you hadn’t noticed, there are other people on the airplane besides you. So don’t clip your toenails, snore with wild abandon, or do any type of personal business under a blanket!”
"There is only 5 of you, and in case you hadn't noticed, you are outnumbered."
Best Answer
StoneyB has identified the sort of scenario where this construction is used sarcastically. in case you hadn't noticed refers to the possibility that the person spoken to may have overlooked something (which ought not to have been overlooked).
Since possibility is involved, the verb is backshifted. In the past, the subjunctive was often used with "in case".