Sorry I flipped the city pair. Coffee hasn't kicked in yet. But LAX/ATL could easily be a city pair that would have a few media people checking a lot of baggage and that would throw off the weight calculations.
The GA is just going to say it's a weight issue, they aren't going to say we have 5 people from CNN who each checked 10 bags and now we might need some people to reschedule depending on what the final numbers come in at.