Avodah Zarah 60 - Idolater Who Fell Into Wine
If an idolater was found standing beside a Jew's wine cistern, then he may have touched the wine. On the other hand, he knows that by touching the wine he will ruin it for the Jew and may have to pay. Therefore, normally it can be assumed that he did not touch the wine, out of fear of being discovered. However, if he has a loan for that wine against the Jew, he can always justify his touching it, and in that case the wine is prohibited for benefit, because of this possibility.
If an idolater fell into a wine cistern and ascended from it, or he measured it with the reed, or he flicked a hornet out of it with a reed - all of these cases actually happened, and the Sages allowed the wine to be sold to idolaters. Rabbi Shimon permits this wine even for drinking, because it will not lead to socializing.
If an idolater took a cask and in a fit of anger threw it into a cistern, the wine is permitted even for consumption.
Art: Ferdinand Hodler - The Angry One