A Tzurbah Medarbanun, unlike a commoner, is not required to swear to affirm he repaid. When the gmara BM 24a asks for what purpose do we need a litmus test to tell if someone is a Tzurbah Medarbanun (bed/Purim, masechta, guest), why doesn't that gmara answer using today's daf regarding thereby being exempt from shvua?
Daniel Gray, TORONTO
A Tzurba me'Rabanan has many rights in the Gemara, such as the right to start commerce in the market (Bava Basra 22a), the right not to pay certain taxes (Nedarim 62b), and the right not to swear. However, the Gemara in Bava Metzia is not concerned with the rights of a Tzurba me'Rabanan but rather with his defining qualities in order to give him back an Aveidah. If he is scrupulously honest except regarding three issues, he can be defined as a Tzurba me'Rabanan and will then be able to receive an Aveidah based on visual recognition.
As for all of the other rights of a Tzurbam e'Rabanan, they may involve other criteria. Rebbi Yochanan (Shabbos 114a) has different criteria for a Talmid Chacham who receives an Aveidah and one who is appointed as a leader or one whose work should be done by others. Thus we cannot bring other examples of their rights to explain the case of Aveidah.
Yoel Domb