I have flown on 4-6 trips during each of the last 2-3 years (both domestically and internationally) and the carry-on baggage can be very stressful. For that reason, I try to get a seat in the back third of the plane so that I load earlier. Most of this can be avoided by the flight crew announcing and enforcing the fact that only ONE bag per passenger goes in the overhead and that they must go in wheels first! Also announcing that once everyone is on board and if there is still room - THEN you may also put your coat up there.
Too many times I see the flight crew walk along and close bins that still have room in them when the plane is only 1/2 loaded.
It is rare that a flight crew actively manages the loading of the bins -- when it does happen, loading goes smooth and there is plenty of room for bags near passengers seats.
(Also agree that the bins above your seats do NOT belong to you!)
So I blame those who think the rules do not apply to them (just enough on the plane to hose everything up!) and also a flight crew that is not actively managing the situation.
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I consider that an infrequent flyer pattern. On EVERY SINGLE one of my UA flights, the gate agents start announcing 15 minutes before boarding that too many/too big bags WILL be gate checked, and to do it now ie before boarding begins. The cabin crew repeatedly announce that one piece MUST be placed under the seat. They protect the bin space for those of us in bulkhead rows.
They DO do all of this, and still people are obnoxious or entitled enough to think that that doesn't apply to them. People on this website and even on this thread apparently don't understand or don't care to understand.
I would prefer to see what happens in the rest of the world; if you make it past security ie if you are on a connecting flight, and bring too much, you are sent back to landside to check in your bag, at your own time and cost. That means that people are forced to take responsibility for their own actions and decisions and not impact the rest of us.