The only possible problem with that argument is that Aaron was with Claire when the hatch blew and he made it off.
Here's my thought on why Aaron IS one of the Oceanic 6; We know that Kate is claiming him as her kid yet she obviously couldn't have been pregnant when they came back so Aaron would have had to come with them.
I don't think that she'd say that she was pregnant on the island because during Jack's testimony in her trial he said that Kate saved them, not something that a pregnant woman would have been able to do. Plus if she were pregnant when they crashed she would have had to of been almost due as Clair was and that makes the argument that she saved 5 other people a little more out there.
On top of that WE know that more than 6 people survived the crash but the outside world doesn't. To the outside world when Jack, Hurley, Said, Kate, Jin and Aaron show up in the US everyone says "hey, six survivors," and that's how the press comes up with a snappy headline like "The Oceanic Six" followed by a happy, smiling photo of the courageous woman and her baby.
My question, though, is what happens to Desmond and Michael and Walt? Desmond is the only one that wasn't on the plane that has the possibility of making it back so how is he explained? Was he just a stranded boat racer that happened to be on the island? Or will he not make it back to Penny from the boat where he is now? And, if not, how's that going to be explained when Penny knows that he's alive now?
As for Michael and Walt, even if you dismiss the idea that Aaron is one of the six, then you can only count Michael OR Walt but not both and still have the "O6." Does Michael stick with Ben's organization and therefore not get counted?
There's still a lot of questions to be answered but I'm going to stick with Aaron being one of the 6 till we know for a fact that it's not him and is, instead, Michael (since we've seen him and we're supposed to know all 6 now).
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