Is it better to point out the truth to people who are mistaken, or is it better to keep quiet and allow that truth to eventually be revealed?
How important is truth to you?
This is a question I've thought about many times.
My thoughts: It is probably better to keep quiet, however if you can't separate yourself from the group and you don't speak up, you can go down with that sinking ship. I've found that proving a point is unnecessary, even a waste of time and effort at certain times.
It's important to work out the facts and the truth and to prepare yourself according to that. It's probably OK to express your opinion, but not worth fighting or arguing over.
On the other hand fighting has its benefits, it can give you strength and integrity if you have to defend your own point of view. It helps you to formulate and refine your truth.