The following actually happened to me with my 1st two Akitas.
For a collar I was using rolled nylon with the two rings PERMANTLY joined so they could never operate as the choke collar they were designed to be. My full grown male was 95# and the female was 85#. They were playing normally, roughhousing while I was watching TV when all of a sudden the play stops with them in an awkward position (together). The male acted like he had hurt himself and the female couldnt breathe properly. Both were about to panic. I saw no immediate sign of the problem until I finally noticed that the male had stuck his paw between the collar and the female's neck, and she had then twisted away from him, creating a tourniquet on his paw with her collar. He was OK (relatively) for the moment, but she couldnt breathe. I hollered for a knife but was able to untwist the kink in a few seconds. But to do so I had to manipulate almost 200# of Akitas with 2 different ideas of what neeed to be done.
I still shudder to think what wouldve happenned if I had not been home and this had occurred. One of my earliest childhood memories is one of an escape artist birddog we had who hung himself, so this really scared me.
Lesson Learned?: I NEVER have a collar on my dogs of any kind unless they are supervised. I realize that's bad if they get out, but I spend a LOT of $ and effort to ensure that will never happen. You might want to think about this.