Case:


Ruling: If valid witnesses testified before beit din that the witnesses indeed violated Shabbat, we would disqualify the witnesses. This is based on the Shulchan Aruch (Choshen Mishpat 34: 1-2) that a rasha, as defined as one who violated aveirot for which the punishment is malkot (flogging) or worse, whether he did so out of desire for the sins or to anger Hashem, is an unfit witness. However, in our case, beit din was not presented with testimony of kosher witnesses of such violations. Rather, they spoke against themselves. Thus, we apparently should apply the rule: "One does not disqualify himself [as a witness] based on his own account but only based on witnesses who testify against him, for one does not make himself a rasha" (ibid.:25).
However, the Hagahot Maimoniot (Geirushin 13:20) in the name of the Ra’avya says that one may accept accounts that would not ordinarily be accepted due to the credibility of the source but are matters that are easy to find out about. Although the Ra’avya discussed a different type of case, beit din reasoned that we can accept the principle regarding matters of a witness’ general public behavior, and thus we should believe the witness when he says that he regularly sins.
Regarding the witness who says that he puts on tefillin on Shabbat and Yom Tov, he demonstrates great ignorance and a desire to lie to beit din. This resembles the Rama’s (Shut 13) case of low-class people whose behavior makes them suspect of being invalid witnesses. He says that they are invalid even without specific testimony about sinning that automatically disqualifies. Rabbi Akiva Eiger (I, 99) questions the Rama, since ignorant or troublesome people are disqualified only rabbinically, and the issue the Rama discusses is regarding matters of Torah level. However, he does not argue with the Rama’s ruling. The Beit Meir explains the Rama as follows. People of such description are at least suspect of being invalid from the Torah, in which case, we have no right to make the husband of the woman about whom they testify divorce her. In our case, there is a further issue. The witnesses’ testimony is to be used to try to force a woman to accept a get against her will, which is something that is forbidden by Cherem D’Rabbeinu Gershom. To allow questionable people to facilitate such a thing would be a leniency, not a stringency, which cannot be done in this questionable manner.