'My d og never wanders." How often have I heard that said? But the reality is different. Gates are left open by visitors and dogs are curious creatures; a passing temptation presents itself and off goes Fido.
With luck, a kind and caring person could find him and maybe call the owner and the dog is returned, but that depends on the finder being able to get close to the strange dog that may not be friendly.
Make sure the swing tag is large with large lettering that can be read from a sensible distance. The dog may have a microchip but that depends on the finder taking the dog to a vet who has a reader. That is unlikely.
Also, are the swing tag and microchip up to date? Or might the information on it be still an old address or telephone number that changed several years ago?
Twice I have found a lost dog and called the details on its tag, only to be told that those people moved away some time ago and the present occupant had no idea except she thought they had moved twice and were some where in France.
After some considerable effort we were able to find a new home for the dog, leaving the original owner bereft. The dog had been obviously very well loved and cared for.
Another essential check is to examine the small hole in which the strong ring has been inserted to fasten the information tag. This could have got bigger and could eventually release the tag so it is lost.
I have just examined Digger's tag, which must be two years old, and ordered a new one at the local 'ferretería', making sure the hole is well away from the edge so it withstands the excessive swinging as Digger bounces away on his exercises.
When you move house, ensure you change the swing tag and microchip immediately as a new and strange environment could cause your dog to wander in search of its original home.