No one in my company is in any doubt as to the chain of command on board an a/c . yet given the locked door policy there is far more CRM involved these days . The captain relies far more on the SCCM to give accurate information concerning problems that occur in the cabin and any course of action the SCCM recommends the captain should take ie diversion due to passenger restraint etc . Respect is a two way process and should always be given .. in doing so good F/D C/C CRM is built and maintained and therefore there is no question of doubting the chain of command