The sign-up was all something we did upon entering the city. I can't speak for the other cities, but it was the case too for Gridania in 1.0, after being chased by a rather angry tree.
For any new characters, they're told to go talk to the Adventurer's Guild leader in their respective city after the opening cutscene. So while those couple of players can choose to believe it's the AG housing the tavern, since there isn't a way to force anyone to believe anything, I wouldn't consider them to be as accurate to the lore.Â
Side Note: Anyone who got the collector's edition bluray (or probably some basic youtube searching  skills to find them) can watch the history section of the game lore and see that the adventuring guilds were made after everything else. If a person starts trying to argue lore, the easiest solution is probably to kindly let them know that's not the case for you, but if you're feeling a little more argumentative or want to prove them wrong, there are sources to back it up.
Other Side Note: There's a little cafe by the airship docks in Ul'dah that are also nice. I've used it to reduce the amount of text flying on my screen, or for a "quieter" setting. You may like it too.
For any new characters, they're told to go talk to the Adventurer's Guild leader in their respective city after the opening cutscene. So while those couple of players can choose to believe it's the AG housing the tavern, since there isn't a way to force anyone to believe anything, I wouldn't consider them to be as accurate to the lore.Â
Side Note: Anyone who got the collector's edition bluray (or probably some basic youtube searching  skills to find them) can watch the history section of the game lore and see that the adventuring guilds were made after everything else. If a person starts trying to argue lore, the easiest solution is probably to kindly let them know that's not the case for you, but if you're feeling a little more argumentative or want to prove them wrong, there are sources to back it up.
Other Side Note: There's a little cafe by the airship docks in Ul'dah that are also nice. I've used it to reduce the amount of text flying on my screen, or for a "quieter" setting. You may like it too.