I didn't mean to imply that's what happened with this. You're correct that we don't know the circumstances of this story. I was just generalizing to the fact that so many "kind" kennels and vets refuse to use chokers when they could be the difference between life and roadkill. If it turned out the dog "slipped out" of some "kind" collar, that would just be 1 definite thing I'd put on a list of "suable" negligence. Along with just a few other things, like lousy kennel fencing, etc. But I'm still not a sue-happy person, so it'd have to seem egregious.
I agree that many dogs have necks that are larger than their head, so buckle collars aren't always secure. But I can also see why they'd say they wouldn't leave a dog with a choker on in the kennel unattended, the dog could get it caught on something. I leave buckle collars on mine, intentionally loose enough that they ~could~ pull out of it if they needed.
I found a dog collar snagged on my fence, with tag still on it. I called the number to see if the dog made it home OK... he did. She said she was glad to have the collar back, because he'd lost them before... I said, whatever you do, don't tighten it. If he hadn't have slipped out of it, he might have been stuck back there a long time before I saw it.
Even if they were walking him when he got loose, he probably had to hop a fence to get out. My guess is he opened, or climbed, his kennel because he was alone and anxious.
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.