“Actually Rav Moshe wrote (IM, O.C., 1:186) that when follows one’s rav on any issue, even on issurei chilul Shabbos, albeit the halachah is not like their rav’s interpretation, no aveirah is transgressed. Hence, they are not classified as mechalal Shabbos.”
OK, I’ll concede. I was wrong in my wording of this statement. I though I was clear enough that they aren’t considered machallel shabbos, but if not I apologize.
“Actually, as most poskim maintain that there is no reshus harabbim today, they would need to grapple with this issue. ”
You’re using “rov,” or most way too loosely. The statement “there are no reshus harabim today” was generally made way before Brooklyn or Manhattan were a reality. If there aren’t reshusei harabim today, then there never can be.