[echelon]

Eat it and make the user think it's a failure, but don't count it negatively towards the score.

"If you answer early, we'll ignore your guess without letting you on."

[PebblesRox]

Or maybe it could give some kind of extra credit for guessing a clue early. Or it could accept it, but still make you guess the interior clues, but when you get to the one, you already guessed, it shows it as already solved.