I have managed a boarding kennel, under NO circumstances would I leave any kind of collar on a dog in boarding. The number of times dogs have died this way is unreal. They catch on anything and they die.
I'm sorry, but I'm talking about transferring the dogs, not simply dogs in an enclosed kennel. There had better be some kind of collar on the dog when moving her around, or "walking" her, etc, but I'd prefer a choke specifically.