This shouldn't be scary folks. I've used my authority hundreds of times. I was always prepared with the facts to back up my decision during the inevitable rug dance with the chief pilot du juor. Sometimes they got angry, but the facts always speak for themselves.
If you don't use your authority as you see fit, the ensuing error could cost you your license. Which would you rather lose, your job or your license?
Captain's authority can NEVER be taken away, it can only be GIVEN away.
Carl