I can only agree with you that from the safety point of view this is worrying. As a passenger the good side of this change is that it’s good to know that I don’t have to worry about being 0.5Kg over, but then as I said above, I’ve never had a cabin bag weighed anyway. Maybe a sensible approach, announced or not, would be to weigh a cabin bag on check-in if that pax is NOT hold-checking a bag. That, presumably, would be the most likely scenario for a really heavy cabin bag. Apart from a heavy landing, I’ve seen lockers come open with turbulence, so I suppose it’s only a matter of time before an incident occurs that makes someone think hard about this rule change.