I was thinking meth...

I see we're moving on to the straw man as well.

Obviously there's something missing to this whole story. Like I said before, the captain is not going to deboard the aircraft without a darn good reason. He still has the company to report to. If that plane doesn't depart on time, people are going to ask/examine why.

As for the cabin crew member challenging the captain, I'll be the first one to say that almost all authority should be challenged; however, to do so publicly in the way that OP suggested they did? Entirely unprofessional. If they really behaved in the way they did (which, to be fair, I'm not convinced is 100% accurate either considering we obviously have an incomplete story here that is being told from a sole perspective - OP's), they should be reprimanded for their behavior, regardless of whether the captain was ultimately in the right or not.

The number of people in this thread that feel the cabin crew member's behavior was appropriate and who feel the captain was out of line is shocking... especially because, again, we are missing the most important details in this story that would explain and/or justify the actions of the captain.

Why would a FA try to overrule a captain for doing something absurd or unreasonable? Would we want to be passengers on a plane that is being piloted by a captain who had to be convinced or coerced into flying his/her craft?

This one does - Virgin's Sir Richard Branson turns stewardess after losing bet

Maybe El Capitan and FA were having an item and had a tiff earlier in the day. The captain wanted to show who's the boss, the FA wasn't having any of it and passengers were just collateral.

I hate to state the obvious, but I suppose many aren't familiar with hub ops. The vast majority of pax at a hub are making connections, so arrival gate is pretty much irrelevant...especially since almost every gate is used in a bank, and many are used overnight. It's a zero sum game for pax. I can give them a close gate (to the terminal/employee shuttle), or I can give them a far away gate and give another plane the close gate.

How do you know this?

How do you know this wasn't an emergency? How do you know the captain didn't confer with the crew?

I think he must have otherwise there's no question that the FA was out of line. Picture the scenario where a captain, out of the blue comes out and says "we're stopping boarding, everyone that's on the plane needs to get off right now." If the captain did not discuss with the FA, the FA would have no idea why the captain was doing this. For the FA to then overrule the captain, without any insight into the reasoning is very scary.

The GA, and presumably dispatch, sided with the captain, as people were kicked off the plane.

Just because the captain doesn't have full command, doesn't mean the FA can overrule the captain. You're saying the GA can overrule the captain. Assuming that's true (I'm not disputing), the FAs recourse is to talk to the GA, not overrule the captain directly to the pax. The FA still does not have authority to overrule the captain, even if other people have authority to overrule.

There was no indication that this was an emergency, the captain implied that it was a comfort issue. I'm not positive on this but I think he even used the word comfort.

To whom?

Are you suggesting that you possess more information than the person who's in the cockpit with all the displays and dials and readouts and other instrumentation and is trained to read and interpret them and how all the systems on the aircraft interact?

Assuming your memory is correct, and you didn't just lead you to read into his words something that wasn't there just to make you feel justified, it's still possible that he said that just to avoid a panic. It may have been something that was merely a comfort issue on the ground, but had the potential to turn into something worse in-flight.

At the very least, can we agree that two airline employees openly disagreeing with each other in front of customers and in fact directly telling customer they are going to "overrule" one another is generally not a good reason to give them a JWD?

There are ways to challenge authority and have disagreements. What OP described, in the situation he/she described, is...not that.

And yet here we are debating a case where the Captain DID decide to evacuate, albeit, at the gate.

On top of that, I think it's silly to compare this case - a case where the Captain made a MORE CAUTIOUS and MORE CONSERVATIVE decision for passenger safety - to cases like Korean Air Cargo 8509 or the Tenerife disaster where it was the junior crew member in the cockpit who recognized something about the situation and their input would have been a more cautious or more conservative approach for safety.

Which CAN become a safety issue. Maybe not for the aircraft while it's on the ground at the gate but it can for the passengers. Passengers could become dehydrated, overheat, etc.

Other than using the word "overrule" I didn't think she was out of line to question the captain, and I'm sure she regretted doing that.
I gave he a JWD because I appreciated the fact that she was willing to try to avoid a situation that caused my family and many others on that flight to miss connections, IMO for no good reason. I also gave her the JWD in case there was some action taken against her for questioning the captain, thinking it might at least give evidence of a different perspective, and someone for Delta to contact if they chose to.

Your actions are admirable. However, if I'm a supervisor reviewing what happened (speaking generally, not about flight procedures since I'm not enough aware of them), this is a case of insubordination by an FA. To me, it wouldn't matter at all whether a passenger thought the FAs actions were acceptable. Presumably, someone reviewing the case knows that there are passengers on the plane that want to get to their destination. And Delta already knows it's bad business to cancel or delay the flight. So that's already taken into consideration in whatever the determination is.

There is a reason the captain has the authority that he/she has. It's not appropriate for the FA to overrule the captain's instructions to passengers, especially when the FA is doing it just to get the flight out, as opposed to, for safety reasons.

I'm surprised by how many people think what the FA did was right. Even if what the captain did was wholly improper, the FAs actions were still inappropriate.