On some Swiss flights they take your carry on bag at the stairs and put it in the hold, giving it back at the stairs when you disembark. Though at LCY you get it back from the conveyor “for security reasons” it seems!!!
Another problem I often witness, is Y passengers putting their bags in the C o/h lockers then walking on to the back of the plane. I think this has been covered several times in other threads, but it remains a frustration.