Originally Posted by Ponyboy
I think this is the only one that's explained in the film without actually explaining it. The regime of crime in Gotham and the corrupt police force (aside from Gordon) are a thread that runs throughout the film. I think that it's easy to deduce that the police either wouldn't really care, or the GCPD didn't have enough men for such a task... or the fact that the Joker had just been on his reign of terror with the Smilex in Gotham... so maybe they just said the hell with it, let the people fend for themselves? The evidence (if there is any) is that the only time you really see a solid police force assembled is at the very end of the movie with the bat-signal. I think that is just another indicator of how the police force was a "useless entity" up until the emergence of Batman.
I don't buy that at all. I don't see the Mayor, Dent and Gordon passing up the chance to net the Joker or give him the chance to kill more people. If they thought they had a chance to catch him then they would have been there ready and waiting with every Cop they had. Even call in the National Guard if they had to. Joker said he would do it at midnight, so they had a time frame to be get prepared.
He said he was going to dump money on the crowd. Unless there's crowds of people on every street in Gotham every midnight, they knew he meant the area around City Hall where the 200th celebration was supposed to happen. After all he said he wanted the 200th celebration to commence even though the Mayor just said they were going to postpone it.
It doesn't make any sense, just like the Joker henchmen already stashed up in the top of the cathedral of all places.