Another thought - with the availability of these machines that make tags -- we had one made for each of our dogs with our cell phone numbers on, that we put on them when we travel.
It might be a good idea to have a metal tag made with the 800 number on to whatever registry you are using for your dog. The only problem with that is sometimes dogs slip collars or people remove a collar.
The thing is if an animal is found, whoever scans the animal is going to contact the company that the chip was issued from - ie: Avid, Homeagain, Banfield, etc.... unless the dog has a tag with different information on it.