I don't know how the collar exactly works, but to me it just looksd like a slip rope with a collar. Slip ropes tighten when a dog pulls hard and though i have never heard it with my dogs a couple of people i know and walk with their dogs make raspy coughing sounds because the lead goes tight, then they stop pulling.
I do not like it when a dog chokes from having it tighten, therefore i always remind my dogs now and then to stay in heel, with a command or gentle tug.