I don’t buy it. I fly more often than most and I can’t remember the last time I saw someone NOT wearing their seatbelt during takeoff or landing.
Regardless, there are people who jump up and start getting their stuff as soon as the plane has landed and sort of slowed down.
Here the plane blew a tire, maybe after it had been on the runway a while. That would cause quite a jolt and, obviously, caused stuff to fall out of the bins. Who knows? Those same people who jump up and start taking stuff out, um, THEIR bins are open and stuff could come out and hit them on the head.
A few months ago I was on a flight where AFTER landing and while taxiing to the gate, some stupid young man decided to unfasten his seat beat and partially stand up. The plane came to a stop as the attractive young female flight attendant, who’d been beauty-queen-cheerful the whole flight, marched all the way back to the rear of the plane where stupid young man was, wearing a look-that-could-kill on her face, and gave him a stern lecture about how the plane would be unable to proceed until he sat back down and fastened his seat belt. It was a small plane, and the WHOLE cabin could hear and turned around to look. Stupid young man turned red, sat down, buckled his seat belt, and will NEVER pull that stunt again. I think they’ve got some indicator lights up front where the flight attendants can see if there are any unbuckled belts. Somehow she knew what was up within a couple of seconds of stupid young man pulling open his belt buckle, because by the time he was actually standing up, she was already back at the rear of the plane.