Yosef Karo, Shulchan Aruch — Choshen Mishpat 25
“ We do not, however, rely on the words of an inferior against someone greater than him in wisdom or number, even if it was a pressing matter, unless there was a great loss at sake. Similarly, wherever an individual opposes the majority, we follow the majority. Even if the majority does not have the same rationale and they each have their own reasoning, since they agree on the law, they are considered the majority and we must follow them. If the city had a custom to be lenient because they received such a ruling from a scholar, they may follow his view. ”
