And still the health and well being advice from British Airways is to walk up and down and aisle for gentle exercise during the flight. So people take that advice, see the belt sign is off and walk the aisle.
Apart from a nuisance to fellow passengers they also get no sympathy on this forum when they are injured in turbulence.
Either you are supposed to be strapped in or you are not. Encouraging walkabout as official guidance helps no one at all.