Interesting. I do wonder about the rationale of wearing seat belts during take-off and landing which is when you need a quick evacuation, although I suppose in some situations during this phase of flight wearing a seat belt may help prevent injury in the event of sudden forces while seated. Once airborne in the cruise with seat belt sign turned off I always keep mine fastened loosely in case of unexpected mod/severe turbulence risking me leaving the seat out of control and being injured either by the cabin ceiling or being thrown back on the floor.