Question Author
Spath, the problem is when the dog escapes out of the house. I don't keep my dog's collar on him when he's inside the house / garden because he jumps up and there's horror stories of dog's strangling themselves on door handles, plus it must be comfier for him to not have it on when he's chilling at home. So if he were to escape, he would be collarless, that's why it's so important to get them chipped!
If he ran off whilst we were on a walk, he would of course have his collar on, with my contact details on it. It's not bother to hop to the vets and wait with them.
Thank you everyone for the kind comments, just doing what any dog owner would have done!