In the story "The Lady or the Tiger" who was the king being unfair to and in what way?

Technically, the king isn't unfair to anyone in Frank Stockton's short story "The Lady or the Tiger." Every accused man has the same probability of proving his innocence or guilt. The king's justice includes a trial in an arena. The accused has a choice of two doors. From behind one door comes a ferocious tiger which kills him, and from behind the other a lady who promptly marries him. The choice of the doors is...

Technically, the king isn't unfair to anyone in Frank Stockton's short story "The Lady or the Tiger." Every accused man has the same probability of proving his innocence or guilt. The king's justice includes a trial in an arena. The accused has a choice of two doors. From behind one door comes a ferocious tiger which kills him, and from behind the other a lady who promptly marries him. The choice of the doors is completely random (until the end when the princess discovers the secret of the doors during the trial of her lover). Stockton writes:

Its perfect fairness is obvious. The criminal could not know out of which door would come the lady; he opened either he pleased, without having the slightest idea whether, in the next instant, he was to be devoured or married. On some occasions the tiger came out of one door, and on some out of the other. The decisions of this tribunal were not only fair, they were positively determinate: the accused person was instantly punished if he found himself guilty, and, if innocent, he was rewarded on the spot, whether he liked it or not.

Of course the argument could be made that if an accused man was actually innocent but chose poorly, the king's justice failed and was truly unfair. On the other hand, if a guilty man chose the lady, justice would again be thwarted. Another argument could be made that the king was terribly unfair to the princess's lover. He was simply guilty of loving above his means, despite the fact "he was handsome and brave to a degree unsurpassed in all this kingdom". The reader can only hope that the princess indicated the door with the lady in order to save the "brave" man.