Well from what I heard, in a 100/200 series it doesnt matter because of 1 pack. And you are not going to get more air pumped into the cabin. I know it sounds crazy, but that came from a MECH. mouth. The 300 Series, it helps to have both engines running with the 2 packs.
Why are our guys doing the single engine taxi. First they think it looks cool, and most of them that do it are a bunch of tools anyway. Its really unsafe, and a couple of pilots have lost there brakes and had to use the emergency brake. Plus our boys/Girls think they are saving the company money!!!! And for what??? We do such a good job flying props, we are now the prop carry of choice.... Yeaaaaaa..