Explanation #1 (Rashi): They are from an orchard in Uzak. This was in Shemitah, and they were guarded.

Question (Rashi): If this was before Bi'ur, they are always permitted [even if they were guarded. If this was after Bi'ur, in any case they are forbidden!]

Answer (R. Tam): (Rashi's premise is wrong.) A Beraisa in Toras Kohanim explicitly teaches "v'Es Invei Nezirecha Lo Sivtzor" - you may not harvest from what is guarded, but you may harvest from what was made Hefker.

Question: A Beraisa in Toras Kohanim, also brought in Bava Metzi'a (118a), says that people who guard Sefichim (things that grow by themselves, for the sake of the Omer and Shtei ha'Lechem, in Shemitah) were paid from Terumas ha'Lishkah (half-Shekalim that Yisre'elim give to buy Korbanos Tzibur);

We should apply "mi'Mashkeh Yisrael" - [Korbanos may be brought only] from what is permitted to Yisrael. What was guarded is forbidden, like I explained!

Answer (Ri): They did not guard them. They merely prevented animals from going there, and informed people that they are needed [for the Omer or Shtei ha'Lechem].

Assertion: Also what is Hefker, one may harvest only through a Shinuy. (Zera Yitzchak - Tosfos explains why we cannot answer the question differently, and say that the Beraisa discusses only skillful harvesting, but through a Shinuy, one may harvest even what was guarded.)

Toras Kohanim teaches "you may not harvest from what is guarded", i.e. even through a Shinuy. This implies that you may harvest, i.e. eat, from what was made Hefker. (We do not infer that one may harvest it normally.)

Citation (Yerushalmi - R. Acha bar Chanina citing R. Chama): This applies in the field, but in the city, even if they did not see a human shadow [we rely on the voice].

Citation (cont.) Question (Mishnah): If one was cast in a pit, and said "whoever hears my voice, write a Get to my wife", they write and give;

Citation (cont.): R. Noson said that this is only if they saw a human shadow!

Citation (cont.) Answer (R. Bun): Shedim are common in pits, just like they are common in the field. (However, elsewhere in the city, they need not see a human shadow.)

Implied question: In Megilah (3a), it says one may not give Shalom to one's colleague at night. We are concerned lest he is really a Shed!

Answer: That refers to in the field, similar to Yehoshua, who was outside of Machaneh Yisrael. (The Gemara asked why Yehoshua greeted the angel, and was not concerned lest it is a Shed.)

Citation: In the Yerushalmi, Amora'im argue about if they found written in a document "Ploni died or was killed", whether or not we permit his wife to marry.

Question: How could Rabanan bring a proof from the innkeeper? She spoke l'Fi Tumah (unaware of the consequences)!

Answer: She was not truly l'Fi Tumah. This that she took outside his staff and bag could have been for testimony;

R. Akiva said that this is not a proof, for surely this is the ultimate speaking l'Fi Tumah, for she cried when she saw them.

Support: The Yerushalmi connotes like this a little. It says that they made her like one who spoke l'Fi Tumah;

Inference: She was not truly l'Fi Tumah. Rather, they bring a proof that she is no worse than one witness.

Pesak (R. Chananel): We hold like this Tana, who does not require Drishah v'Chakirah.