פירוש על עבודה זרה 138:20

Rava says that in the first clause the pure things remain pure because the owner could come back in some roundabout path and they would not see him coming. Since they cannot see him coming, they will be afraid to touch the food.

This interpretation gets closer to the simple meaning of the mishnah. In the second clause, since he told them that he was going away, they will not worry that he is coming back very soon. Therefore, even if the owner could surprise them by coming back on a roundabout path, they will not be concerned.

If the mishnah had taught only the first case where they were transporting jars of wine, I might have thought that the reason it is permitted there (if it was presumed that the wine was under guard) is that the non-Jew is worried that the Jew will come back and see him drinking the wine. But if the Jew leaves the non-Jew by boat or by wagon, the non-Jew could simply travel a bit away and do what he wants. Therefore, the mishnah had to teach us that even in this case the wine is permitted (as long as the Jew did not tell the non-Jew that he was leaving).

If the mishnah had taught only the case of the wagon or ship I might have thought that in that case the non-Jew is afraid that the Jew will sneak up on him and therefore he would not drink the wine. But if he’s left in the shop, the non-Jew could lock the door and do what he wants. Therefore, the mishnah had to teach that in both cases the wine is permitted, again, as long as the Jew does not inform the non-Jew that he is leaving.

According to R. Yohanan, the rabbis are more stringent than R. Shimon b. Gamaliel in the case of a stopper of lime, where a hole could be sealed relatively easily and not detected. If, however, the stopper is of clay, where a hole could not be sealed, then all agree that the wine is prohibited only if he is absent long enough for the non-Jew to make a new stopper and let it dry.

The Talmud quotes a baraita to refute R. Yohanan. In this baraita R. Shimon b. Gamaliel says that if he bores a hole in the stopper, the hole will be seen on both the inside and outside of the stopper. Therefore, R. Shimon b. Gamaliel is concerned only if the Jew is absent long enough for the non-Jew to make a new stopper.
But this makes sense only with a clay stopper. With the lime stopper one could not detect it on the outside because the lime can be smoothed out and made to look as if it was not tampered with. Thus Rabban Shimon b. Gamaliel assumes that the rabbis state their opinion in the case of the clay stopper.

This is R. Yohanan’s answer. R. Shimon b. Gamaliel did not know what type of stopper the rabbis were referring to. If they were referring to a clay stopper, then the stopping could be seen on the inside or outside. This is what he said in the baraita. But he also said to them that if they were referring to a lime stopper, the stopping can still be seen on the inside. This will deter the non-Jew and the wine will be permitted under the assumption that the Jew did not leave the wine alone with him for long enough.

According to R. Yohanan, the rabbis disagree only concerning the lime stopper. Since the stopping can only be seen on the inside, the Jew might not turn the stopper over to see if it had been tampered with. Knowing this, the non-Jew might bore a hole and drink some wine. Therefore, if he has long enough to do so, the wine is prohibited.

The last clause of the mishnah does not contain a dispute between the rabbis and R. Shimon b. Gamaliel and yet seems to follow R. Shimon b. Gamaliel’s opinion. This indicates, according to Rava, that the halakhah follows Rabban Shimon b. Gamaliel. In other words, the editor of the mishnah hinted here that the halakhah follows Rabban Shimon b. Gamaliel.

The Talmud raises a difficulty—obviously this last passage follows R. Shimon b. Gamaliel. Why did Rava need to even state thi? The answer is that we might have thought that this last passage was actually stated by R. Shimon b. Gamaliel. If this were true it would not be a case of the mishnah following him, but just R. Shimon b. Gamaliel again stating his opinion. To teach you that this is not the case, Rava says that the halakhah follows R. Shimon b. Gamaliel because the anonymous mishnah follows him.

The Talmud here offers a rare remark on current practice. Theoretically, the rulings have consistently followed the lenient opinions among the tannaim. We are not concerned with a hole being bored in a jar nor are we concerned that seals will be forged. And yet, Jews do not leave wine in the hands of unsupervised non-Jews. Why not? The answer is that we fear that the non-Jew will use the bunghole to extract some wine. Rashi says that this is a small hole put in the side of the jar to let some smell out. Perhaps, Jews fear, the non-Jew will slightly widen the hole and take some wine out.

Jews may visit (or host) non-Jewish prostitutes. But, according to Rava, they will not transgress the prohibition of drinking yayin nesekh. Therefore, we can assume they will not let the non-Jewish prostitute touch their wine. As an aside, in light of human behavior, this does not seem at all shocking. It is not uncommon to see people who are cautious about ritual laws be more lax on moral ones.