There’s a story, possibly apocryphal, about the Israeli Cabinet, after the surprise attack that started the Yom Kippur War, always requiring a “tenth man”. The theory is that if nine people agree, then it is the duty of the “tenth man” to disagree, no matter what and no matter how much the other members pressure them. They are considered irritating but necessary to avoid dangerous group think.

I’m not sure I completely understand what you mean by a jabroni. Do you think they are the “tenth man” of our communities?