It is, Ive witnessed cabin crew refuse or ignore multiple times, and clearly says so on their website too that passengers must be able to put luggage in the bins themselves. Makes sense to me, if you can't lift it then it's probably overweight and should of been checked in. Obviously I'm sure they'd make exceptions for unaccompanied children, height challenged people, injured, the very elderly, those with noted back issues, 1st class passengers maybe. Seems a reasonable policy, faster boarding, reduction in abuse, space for others, etc.. https://www.britishairways.com/en-us/information/baggage-ess... It all about small nudges, disincentives to affect future behavior, back to the Singapore airside carpets. Others do pick up the slack indeed, and usually both ended up with a quick moan, whilst I really wanna comment you selfish .#*@ that suitcase is taking up half the bin, where do I put my bag, or good forbid you try put that 20kg on top of my small rugsack

It's for the safety of the cabin crew. If they had to help put people's heavy bags in the overheads on every flight, they would quickly get back injuries. It's fine for the passengers because they are not doing it often.