Jackson (Border collie/Corgi) and Solo (Cardigan Corgi) play with a gusto I've never seen. Much of it is a wrestling match where one grabs the other by the ruff of the neck. There is pulling, tugging, taking to the ground, and twisting acrobatics--like nothing I've ever seen before.
I've heard horror stories of dogs strangled by collar mishaps (see here). I've not experienced an incident or close call, in 21 years and seven furkids. But I've read stories here and there, and have met some dog people who are strong proponents of not collaring a dog if you aren't present right beside them.
Watching them play in the lawn Sunday morning, months of thought crystalized clearly. "Take off the collars," I said, and the dogs were uncollared. In our ten years in Oregon, we've never had a dog go walkabout. Not that it can't happen, but it's not likely. And looking at them twist themselves into pretzles, with mouths around collars, it suddenly seemed that was a much more likely, and more dire, situation.
They are all chipped, of couse, Collars will be worn when out and about (dog park, vet visits, traveling).
They feel and look so wild without them!