Observation: If a man is staring at another man, the second man won't stare at a woman that he would've otherwise stared at if the first man hadn't been there.
Objection 1: Because the second man would rather stare at the first man?
Answer: No, because he's conscious that what he's doing is shady and doesn't want other men to know that because of some unwritten universal bro code (not that the first man and second man in this - or any other such - scenario are 'bros' but please work with me here).
Objection 2: But if the assumption that all men are shady is right, then they could both go wink-wink and then stare at the woman together!
Answer: That's right. But - and it's an important but - I'm talking about situations where the first man has chosen to stare at the second man and not at the woman and has thus already made his moral choice. The second man knows - as all men know - that staring is wrong. They do it anyway because they think they can get away with it.
Objection 3: How do you know that the second man would've been staring at the woman anyway?
Answer: Because that's what men do. (Sad but true.)