If that were the case then there won’t be anybody taking advantage of the loop hole. A few years ago I was staying with my brother (and family) for a few days in Chicago suburbs and we both were going to fly to Charlotte to visit my parents. My brother and family booked a flight from Milwaukee to Charlotte which had a stop over in Chicago as the flight was cheaper than going direct from Chicago.
I paid more and met him on the same flight from Chicago to Charlotte so I didn’t have to go to the airport at 3am.
If my brother didn’t have check in luggage and/or car at the airport, he could have gotten off at Chicago and not taken the last leg to Milwaukee. The seat wouldn’t be available to sell if the flight was full.
As far as flights never delaying for missing passengers, I have seen it often. I have sat on flights where they have announced they are delayed as they are looking for a missing passenger because they know they have their luggage on board or delayed to having to remove the luggage for a missing passenger.
My friend was on a flight in December that had a connection that he thought he was going to miss due to his first leg being late. When he asked the crew, he was told not to worry that he second leg wouldn’t take off as it was mean more than 20 other passengers would miss the connection. They may have hid the reason it must have seemed a cheaper solution to the airline to delay the last leg due to the number of passengers that would have been to been rebooked and put up in hotels, etc.
These may not apply to somebody trying to game the system but I wouldn’t say a flight will never by delayed to missing passengers.
I typically fly 50 to 100k per year though almost all my flights are international. I only fly back to the US about once a year so don’t experience a lot of domestic US travel these days. So maybe a different service level seeing staff trying to chase down missing passengers.
Airlines often find themselves almost fully loaded as much as half an hour before scheduled take off time, and then may send cabin crew (not official gate crew who stay glued to their posts) scurrying out looking and screeching for the missing few.
I know because I have been screeched at while still enjoying a beer with plenty of time left before the announced boarding time…
One time, on a business trip maybe 20 or 30 years ago, a colleague and I were late getting to ZRH due to missing a train followed by a very rare train delay. We RAN to the gate just to see the plane being pushed out towards the runway. It was literally 10-15 feet pushed out already. The gate agents were still there and closing up. They saw the two of us run up, and did something on their phone, and suddenly we see the plane being pulled back into the gate. They very quickly opened the door, we entered, they closed the door AS WE WERE WALKING to our seats, and were pushed out again while we were fastening our seatbelts. We were absolutely shocked, and doubly shocked that this could happen in Switzerland, the land of super punctuality. I’m pretty sure that I posted about that experience here on the MF boards back then (maybe on LBYM or REHP boards).
I was on a business trip returning home across country on a 7pm flight. But my meeting was short and I was able to arrive at the airport at ~3:45 and there was a 4pm flight. They booked me standby and told me to rush to the gate.
It was a long run at a big airport.
The door was closed when I arrived at the gate and the agent said there was 1 empty seat but they were going to wait 15 minutes because the person had already checked in.
Then 15 minutes later they said the seat was mine but first they had to offload the no-show persons checked bag.
None of this was communicated to the people sitting on the plane.
When I walked on EVERYONE stared at me wondering who the heck I was.