Airline responsibility during connection

If you arrive after the gate is closed, there is no amount of yelling and screaming that is ever going to get it re-opened, as doing so has various implications for labor contracts and safety checklists and so forth, and will result in delaying all the other people already on the aircraft and possibly those waiting to board the plane after it arrives for its next leg.

If the door was still open but the gate agent had already cleared standby passengers thinking that you weren't going to make it, I think it's also unlikely they'd tell those passengers to get off again. Certainly after last year, United knows that a confrontation over a passenger who refuses to give up a seat can go about as bad as any incident can go in terms of public relations.

And you can and will miss a connection on any airline; I slept on a bench in Terminal 2 of O'Hare on the night of Christmas Eve once thanks to American.

As for the part of your question that is not a rant, they tell you exactly what their obligations are to delayed passengers in the Contract of Carriage, Rule 24, part E, Irregular Operations. UA defines a Delay in scheduled departure or arrival of a carrier’s flight resulting in a Misconnection as an example of Irregular Operations, and carefully extracts itself from any obligations to those passengers beyond arranging alternative transportation or a refund.

Part F covers Amenities for Delayed Passengers and describes the things United can offer, but only at its option, in the event of an extensive delay caused by UA. The interpretation of extensive is presumably left to the staff. You are entirely within your rights to disagree with the staff's position and attitude, and to withhold your business as you say you have done, and to inform others about it, but as a matter of law it doesn't seem there is anything you can demand of them from a court or a regulator.

To choster's excellent answer, I'll add a couple things:

• Some countries may provide you with additional rights. That doesn't apply to your flight out of Miami, but if you're flying out of the EU, you're entitled to compensation and assistance under the terms of Regulation 261/2004.

• United's delays and cancellations page is pretty readable. It includes their policy on paying for hotel rooms and meal reimbursement if you are delayed overnight due to a problem within the airline's control. If that policy isn't being followed, you can ask to speak to a supervisor. Other airlines will have their own policy.

• For major delays where you've been treated poorly, the airline may, as a matter of customer service, provide some compensation if you complain to them after the fact. This would be less likely if the delay is short or due to weather or air traffic control, more likely for a mechanical problem within the airline's control that caused a lengthy delay. You can write the airline's customer relations department requesting compensation in a succinct complaint listing what happened and the extra expenses you incurred as a result, and you might get some frequent flyer miles or credit toward a future flight.