Im sorry, Ive said too much already.
It seems to me that the only reason to continue to keep it secret would be if we were supposed to keep trying to find it.
And if that is the case, there should be some sort of notification that it still exists and we should still be looking for it.
Otherwise, if the search has concluded, there should be some sort of recognition of the first several people to find it, and the rest of us should be let in on the joke so that we can enjoy it as well.
(I'm not trying to pressure you into breaking any sort of promise of secrecy, but rather criticizing the people responsible for managing this event.)