Don't worry about it. The fuel will weather out of the teak fairly quickly. We've had the occasional splash onto the deck planks and it's gone when we come up to the boat the following weekend.
These days I pour a small pail of water on the deck at the deck fills (before removing the caps
) and this seems to prevent any splashes from soaking into the boards. But even before I started doing this, fuel "stains" disappeared on their own in pretty short order.
That's with natural (no finish) teak deck planks. I have no idea what would happen if one has Cetol or oil on their decks as we don't do that and never would.