It just goes to show how doing something slightly odd at the round table is potentially enough to get you banished straight after, because when people have no idea who a traitor is they latch onto anything that sticks out and then the herd mentality immediately follows and it becomes a case of safety in numbers.
I can just tell if Brian does leave, those who voted for him will get defensive and say things like "well, he shouldn't have acted that way" - just as they did when they banished Sonja. Whereas they should learn from it and say "maybe jumping on someone who's a bit anxious isn't wise considering it's an anxious experience for everyone". Maybe some will...
A strategy that might work is studying the expression on each person's face when they're nominated. When faithfuls nominated Ash she had a different expression to when Paul and Harry nominated her, I suppose because the latter made her feel pretty defeated and betrayed. I was thinking if you saw that reaction in someone who gets banished and says they're a traitor, it identifies at least one more traitor. But I know it's easy to say that - it's very different when you're in the situation!