
When you travel it's important to have a proper ID for your pet's collar. Print your cell number and your address on the collar and to be safe have another tag made with your friend's number and their address as well.
It might sound a bit over cautious, but it's important to always have as much identification on your pet's tags as possible. In the event that your pet gets lost there is a much higher chance of finding your pet with proper identification. You can never be too safe.