Your dog's collar.

Yes it would, for ID purposes, but if he gets caught on something he won't strangle himself!

When I had a dog, he was collarless. they seemed to bother his throat & he would barf. but when I removed the collar, he didn't get sick.

He just had a very sensitive system. He was well trained to there was no issue of him running away. If he wasn't in the yard, we knew where he was. he walked around the block to go see the other parent (our parents split up & dad moved around the block)