Spoiler warning - Christopher Nolan's take

Rating: 10/10 (2 August 2008)

Batman insisted to create a white-lie to protect the white knight image of Harvey Dent, he said, "Sometimes, truth isn't good enough, sometimes people deserve more. Sometimes people deserve to have their faith rewarded."
Christopher Nolan wrote into the script the citizens' refusal to detonate the other boat's bomb for the same purpose, for us.
In Memento, Nolan has the presumed hero fall when the test came, deciding to live on a lie just to preserve his own need to live. In this film, the only moral victory from the 'people' came from the two boats. But the "good boat" representative's final refusal to detonate is unconvincing, though plausible. What will we really do? I wonder if Nolan did that for us, to give us a little hope in ourselves though it might not be true.