Originally Posted by Anno_Domini
And with Crane...it was always shown that his gas could work outside of his mask from his wrist(as seen in the first meeting between Batman and Scarecrow), but the mask was just to mess with the people who does inhale that fear gas.
Sorry but you misunderstood me. What I meant was that the people of the Narrows freaked out without even seeing Scarecrow's mask - just because of the fear gas.
They main reason Nolan let Crane wear his mask in BB (the same goes for Joker's white facepaint, green hair and purple suit or Selina's catsuit and domino mask): He had to resemble his comic counterpart. Others than that a simple gas mask would have done the job.