2 Bible

You got something wrong at the beginning of your question. It seems to me that running to the court of appeals is a matter and not a law, in order to show the likability of the subject and the agility in the mitzvot. And this is the matter of agility in all the mitzvot as detailed in the Miselat Yesharim. The question of how we know what is law and what is a matter is a good question and I don't have a good answer for it. Interpretive intuition. Rabbi Volba once wrote that the criterion is what appears in the Rif, but this is of course far from accurate.