Avodah Zarah 70 - Alibi for Entering a Wine Cellar
If an idolatrous harlot is having a meal with Jews, Jewish wine at the table is permitted, because they are interested in her, but not in making a libation of wine. On the other hand, if a Jewish harlot is having a meal with idol worshippers, her wine is prohibited, because she will not protest if they pour her wine as libation.
If an idolater is found standing among the barrels of Jewish wine, then Rava's rule applies: if the idolater has a way to evade a charge of burglary - the wine is forbidden, and if not, the wine is permitted. If an idolater has an alibi to explain why he was found there, he will have the desire and the presence of mind to make a libation. Even if the alibi is not perfect, as long as it saves him from being prosecuted for burglary - this is enough, and he will be willing to take the risk that someone may discover him while touching the wine. Without an alibi, he will be too nervous to make a libation, and we presume that he entered for a different purpose. The Talmud gives twelve cases explaining this rule.
Art: Gabriel Metsu - Portrait of the Artist with His Wife Isabella de Wolff in a Tavern