At LHR I was very surprised to be asked (at check-in) to weigh my carry-on - Business Class flight. The check-in agent said this was for "Health & Safety reasons as the luggage may fall from the overhead & injure someone"....my bags were overweight. Never had this before & indeed they were borderline aggressive about it, IMHO. Was told I could re-pack my bag (I had 2x bags actually) to ensure each weighed no more than 7kg before boarding the aircraft. I didn't do that & was never challenged again throughout my entire 2 sector journey.