It’s easy to see why joining a third person is so effective for peer pressure at a table of 7-8 players. Imagine you were standing in a room of unknown people, and you were prompted to share an opinion about something controversial, that’d make other people in the room potentially want you dead.
If you shared your controversial thoughts, making at least one enemy, that’s a kind of scary place to be. But then, if two strangers openly agreed with your opinion and welcomed you, how would you feel? It would be pretty hard to think of yourself as wrong, and it’d also be somewhat difficult to suspect these two people are manipulating you. After all, you only voiced your own idea, and they’re just agreeing with you.
In the scenario where a third player declares your partner as Brutus, things may sound bad at first. However, given that most captains like double-kills, you have the opportunity to convince the table to kill Brutus’ mark. You could even volunteer the killing blow yourself to stop “Brutus” from winning the game.
Oh, someone else was Brutus? Oops! ^_^;
That was a specific example, but if you keep your ears open to these kinds of opportunities, you’ll notice plenty of advantageous opinions to pile onto. After all, most of Captain’s Gambit is about sharing opinions regarding who should die, and RJ will say yes to most answers.
So if any third player gets a notion that would be beneficial for you and your partner, take your advantages and allies by stoking those flames. Especially if they get people dead.
The extra benefit of applying group pressure is that contrary opinions become unpopular opinions, which then get stifled. For example, if everyone agrees to kill a player with too much blood, an outcast will have a hard time articulating why it’s a bad idea.