Re: Limits of Captains authority
Well the 100-ton license I hold does say "Master" of steam, motor, sail 100tons, etc. The 6-pack may indeed still say "operator", in fact the 100 ton used to be called "Ocean Operator" if I recall.
That doesn't make everyone else "slaves". But in matters of safety and seamanship, the captain should have the last word, as anarchy tends to be unsafe in a crisis. On a commercial vessel, the crew are employees and have to do what the "boss" says unless it's illegal or obviously unsafe.
With passengers or recreational guests and especially with paying passengers, it's more of a caretaker status. I work for you, and treat you like a guest, or a student, or a passenger as the case may be. When I tell you what to do (put on a lifejacket, move to the other side, get below decks, keep a lookout on somethng) it's for everyone's benefit, assuming I know what I'm doing that is.
And "orders" work best if wrapped in honey rather than vinegar. this is true ashore as well.