A few things here...

If you started in Gridania, you arrived on a carriage after sleeping most of the trip. It would be simple enough to assume that your carriage was inspected at Quarrymill on its way through. Ergo, you must have passed "customs" and given you got the blessing of light en route, the elementals were probably very happy to have you. And the twins and trader, because Scions.
Furthermore, when you arrive in Gridania, you are <required> to present and register at the adventurer's guild in the Carline Canopy. No, seriously, the Wood Wailers won't let you even approach the aetheryte plaza citing your need to be registered.

If you started in Limsa or Ul'dah, you arrived as a diplomatic envoy of your respective city-state. The Elder Seedseer herself was expecting you, who communes with the Elementals daily, and presumably arranged for your non-woodsinful admission to the Twelveswood. Seriously, can you imagine what would happen if a Limsan Marshal were mauled by a Treant on arrival? Stillglade Fane isn't that dumb.

Your good deeds from that point are sufficient evidence of your character to the elementals that the rest is, as they say, history.