My wife saw this item in our local paper.
Upon checking in for her flight, a lady was told by the ticketing agent that her large, checked bag was too heavy. The agent suggested the lady needed to remove some items from it and put them in her carry-on bag. The lady pondered that for a second then sagely responded, "Why do I need to do that? Aren't both bags going to be on this aircraft?" and so it goes . . . 
Without getting into the minutia of cargo distribution and aircraft weight and balance, or a discussion of overweight baggage fees, it does make one wonder. 