@isrnick:
To what exactly are you referring to? The whole Luffy just became famous and Ace was traveling thing?
It is invalidated by the same answer… It wasn't even specified in the letter something like "lets all meet again only if we all become famous, and only when the 3 of us become famous, never before" (it would even be kinda lame), so what did Sabo do the whole time while Ace was famous already and wasn't hunting Teach?
And I quote Sabo: "Where I'm headed… well, somewhere that's not here... And then I'm go to grow stronger and become a pirate. I'm going to become a freer pirate than any other, and meet up with you two somewhere again. We'll meet again someday for sure, out on this wide, free ocean!!"
First, what's freer than being "dead"? Second, I have been refering to the part where he says we'll meet again on the ocean. I'm also assuming that he was going to wait for Ace and Luffy to out on the seas, rather than just meeting up with one of them and then the other. The only way he could know that they had made it to the ocean is when they get bounties. Since Luffy just got his, and Ace was already on the hunt for BB, that doesn't make it easy for Sabo to get them all together.
The ship he stole was on there on the harbor of the island, where the Teryuunbito were gonna disembark, so he had to pass in front of that beach to reach the open sea… He certainly wouldn't have shown himself in front of all that people if there was an option, he was trying to runaway after all... Again, Sabo wasn't dumb...
They were making a reception to the World Goverment agents, so they weren't exactly gathering cannons on the beach and getting read to shoot any ship who could appear nearby, and by the time someone would get something and try to shoot him he would be out of reach... Besides it wouldn't look welcoming if right when the WG's ship was reaching Goa Kingdom's coast there was someone shooting in their direction, or even shooting some random ship on the coast, it would look like there was some kind of problem happening on the island and they wanted to make a good impression.
And it was the perfect moment for him to escape and not be followed, because there wouldn't be any other ship of Goa Kingdom in the coast of the island, and if someone would try to go after him, by time they got a ship ready to sail and had gone after him he would be too far away.
The perfect moment for him to escape would have been in the middle of the night when no one is watching the ocean because everyone's asleep. The absoute worst time to leave ould be when everyone is at the beach and the world nobles are coming. That is, unless you want a lot of people there to see you "die"….
Well too much past this point and we're just going to spit out the same theories over and over again, and Oda's playing games with us by taking a break, so we'll just have to wait two weeks to fins out something more. Until then there is no definate proof for either side, which, I'm sure, is exactly how Oda wanted it.
So until then, as I survived the buster call said, Sabo is Schrodinger's cat. He is both alive and dead until the box is opened.