Continuity mistake: When Alfred finds a match to the fingerprint we see Bruce pushing the motorbike in the background. Camera cut and Bruce has stopped pushing the bike, got on, and is sorting his helmet out. (00:58:10)
Continuity mistake: When Fox is showing the sonar to Bruce, the way Bruce holds the phone changes between shots. (00:32:25)
Revealing mistake: When the Joker shoots the bank manager and he stumbles to the floor, you can make out the shape of knee pads under his suit. (00:04:40)
Continuity mistake: The bank manager shoots one robber in the back with the shotgun. We then see clown dive behind a counter for cover. In this shot, the manager has left the office and is a fair distance away from it. Camera cuts and he's just outside his office again. (00:04:00)
Revealing mistake: Gotham General blows up but it appears to be an abandoned building. The shot pulls out after the Joker gets into the bus and you can see sky right through the building.
Revealing mistake: In the scene after Batman thwarts the Joker's attempt to kidnap Harvey Dent by making the lorry the Joker is driving crash, the Joker crawls out of the lorry, picks up a gun and starts firing. In the background on the right alongside the Joker is a shop with the sign 'Sweet Home Chicago', where the scene was filmed - it should be Gotham. (01:18:35)
Continuity mistake: During the chase on the Lower Fifth, the lead SWAT van is hit by Peterbilt on the passenger side (with the driver side facing the water). When the van crashes through the barrier wall and goes into the water, it is facing the wrong direction. (01:15:50)
Visible crew/equipment: When the Joker places the smoke grenade in the bank manager's mouth, a wire or tube can be seen on the left side of his face. It's only visible in the shot when the string pulls the pin, as soon as he drives away in the bus.
Continuity mistake: On lower 5th, the SWAT driver yells lock and load. When he does he has 2 cable ties in loops on his left hand side of his jacket that are exactly equal in size, both the loop and the "tail." We see outside the van for a few seconds. When the camera returns to the driver, the loops are now different sizes as evident by one having a longer "tail". (01:14:00)
Revealing mistake: The Lamborghini Murcielago that Bruce Wayne drives changes from a real Lambo to a fake one - in the long shot (down an alleyway) showing the Lambo at the end of the street, It's obvious the wheel base is too short and the ride height is too high. It makes no sense why they would use the fake Lambo in this shot, as the car doesn't get damaged until later in the film. (01:46:00 - 01:51:00)
Revealing mistake: In the chase scene, the police helicopter appears to have NYPD markings instead of Gotham Police. (01:12:00)
Answer: It's habit, and a sensible one at that. When he's in the mask, when he's being Batman, he uses the voice, even if the person he's with knows who he is. If he drops back to his normal voice with some people, it sets the precedent for using it while wearing the cowl, which means that he's more likely to slip up and use it around people who don't know, potentially revealing his true identity. If he sticks rigidly to using the voice when kitted up as Batman, regardless of situation, it minimises that possibility.
Tailkinker ★