From what you quoted-
C H A P T E R I V
MISHNAH. WHERE IT IS THE CUSTOM TO DO WORK ON THE EVE OF PASSOVER UNTIL MIDDAY ONE MAY DO [WORK]; WHERE IT IS THE CUSTOM NOT TO DO [WORK], ONE MAY NOT DO [WORK]. HE WHO GOES FROM A PLACE WHERE THEY WORK TO A PLACE WHERE THEY DO NOT WORK, ON FROM A PLACE WHERE THEY DO NOT WORK TO A PLACE WHERE THEY DO WORK, WE LAY UPON HIM THE RESTRICTIONS OF THE PLACE WHENCE HE DEPARTED AND THE RESTRICTIONS OF THE PLACE WHITHER HE HAS GONE;
AND A MAN MUST NOT ACT DIFFERENTLY [FROM LOCAL CUSTOM] ON ACCOUNT OF THE QUARRELS [WHICH WOULD ENSUE]. SIMILARLY, HE WHO TRANSPORTS SABBATICAL YEAR PRODUCE FROM A PLACE WHERE IT HAS CEASED TO A PLACE WHERE IT HAS NOT CEASED OR FROM A PLACE WHERE IT HAS NOT CEASED TO A PLACE WHERE IT HAS CEASED,1 IS BOUND TO REMOVE IT.2 R. JUDAH SAID: ‘DO YOU TOO GO OUT AND BRING [PRODUCE] FOR YOURSELF.3
This in actuality proves that its the Minhag of the place and not of the father necessarily. UNLESS perhaps one can make the claim that today the Minhag of the place is to follow one's father's minhag. Or its the custom of this or that place to follow one's father's custom.
Also another issue is if it was correct in the first place to establish this custom (assuming so because a custom made by the people isn't necessarily on par then with a custom made by the Hachamim and the question would be if more Hachamim agreed to it or more Hachamim disagreed to it, which if I remember the video claimed that more or the majority were opposed to this custom and the Rav quotes a number of Askenasi Hachamim who opposed it) if it is binding upon a local (say America) over which this custom was not established in, but carried over. And would or does such a thing carry on from a different local or not.
