When I hired out we could still kick cars at certain locations in Southern CA, and we could also switch without air. They eliminated them both years ago, but I know it's still a common practice at different places around the system.
Switching without air is so much easier, and saves a lot of time. If the cars are loads, they will still roll without knocking off the handbrake. So just go to a hook, shove or pull the cars around as needed. No saying "going in between" on ever car, waiting for a response of set and centered, lace up the hoses, open the angle cock, climb on the car to knock off the hand brake, report in the clear and then start your movement. Repeat for cutting the cars off. Do that for every car at an industry, say 10 -12 times... takes time.
Just like cutting the "helpers" in on the rear of a train.... The helpers make a reduction at least 5 lbs deeper than the train has set, to make sure that the train brakes don't release when the Helpers cut the air into to their power. If the engineer were set set the same or less, the train brakes will start releasing, and the train will start to roll. Then you have some unhappy trainman as they have to go tie it down 
