Not sure what language Delta has, but at U, the Captain is the on site leader from the moment he/she arrives at the gate. Have had numerous occasions where this theory is tested. For example: it’s the last flight of the day. We have a handful of pax who will be stuck overnight if we leave without them. Overzealous gate agent says “my boss in zone says to button it up, we need the on time”. I call zone, tell her boss we’ll wait for them. Case closed. There are may other examples, but you don’t have to give them orders per se, you simply don’t release the parking brake until things are done. There are no second guesses from the Chief Pilot, and no paperwork required. Just doing what we get paid for. Not really sure why some on this thread don’t understand this simple concept. Perhaps pre-merger CAL did things differently, but those days are looooong gone.