The Carry-on issue is completely different.
There are exceptions about the carry-on rule....if there was a handicapped person bringing on a carry-on...then it's actually a carry-it-on the plane...not rollerboard packed to the hilt and can't lift it, kind of thing.
The company, (AA), has been throwing all this 'cart safety' info out to the F/A group...how to move the carts 'smart' without injuring oneself....but they fail to inform the traveling public about how overstuffing your carry-on will hurt not only you, but the F/As trying to lift something they have no clue how heavy it actually is.
I tell my F/As to not even think about lifting anyones bags because I don't want 1) them to be hurt trying to lift an elderly womans bag that has 600lbs of books/rocks in it, 2) I don't want to have the F/A injured creating a delayed flight, 3) wait for a replacement F/A because someone requested a F/A to lift something that wasn't their own...
However, you would be surprised at how heavy bags can get from those elderly people....I wouldn't want my 96y/o grandma to lift a bag that heavy...but again, if you can't lift it above your head, then it's no longer a carry-on....there is a limit, and it should be enforced.
/rant