catch yourself,
“Yes, according to Rav Moshe v’siyato, anyone who carries in Brooklyn on Shabbos is mechalel Shabbos. If they are ill-advisedly listening to someone who thinks there is a valid Eiruv, they are not Reshai’m, but this does not change the facts of the case.”
What, Rav Moshe maintains that we need three million people over 12 mil by 12 mil square area to be classified as a reshus harabbim. Brooklyn does not contain such a population over such an area. Brooklyn is encompassed by mechitzos, and Rav Moshe would allow as well.