Earlier quoted context omitted.
Unrelated to their inflight entertainment, United pulled this stunt on me the other day. - Flight at 11AM, boarding at 10:20. - Show up at 10:25, boarding doors are closed. - "Didn't boarding start 5 minutes ago" - "Yeah we close the doors once 95% of people show up, sorry, you should show up when boarding starts" - "Yeah but didn't boarding start 5 minutes ago, how was I to know" - "You should have known, sorry"
>Yeah we close the doors once 95% of people show up So they are essentially scamming 5% of passengers out of their tickets?
There's a bit of a checklist of things that need to be completed after the door gets closed and the gate pulls away. They're often incentivized to try and speed things up, so if there's nobody at the gate anymore to board they might assume those passengers decided not to go on the flight. Especially with people now checking into flights the day before, the airline may not even know if the passenger is even at the airport and would realistically show up to the gate anytime soon as checking in means pretty much nothing these days.
They're not scamming anyone. Your ticket said you were supposed to be at the gate to board at a certain time. You weren't there, so you missed the flight.