If you asked that question, there could only be two outcomes.
One possibility is that the villagers insist the fat pig isn't the one they threw into the river, and the reason is simple: our fat pig has already been taken by the Dragon King!
The other outcome is that everyone starts panicking: the fat pig offered to the Dragon King wasn't accepted? What are we to do? Does he disdain our offering as too meager, now leaving us to fend for ourselves? Should we send a cow down instead?
If it were the first outcome, it would be manageable; it would just mean that as the person in charge, I'd be criticized by the villagers again: you saw the Dragon King take our fat pig, so why ask with such intentions?
If it were the second outcome, with people's unrest, should anything chaotic arise, could a small manager like me take that responsibility?
So, this particular fat pig absolutely couldn't have fallen into the river section I am responsible for...