It may be worth mentioning as well that you can provide some basic contact info on the lock screen. Settings ... Users ... Owner Info and enter something appropriate. Check the Show owner info on lock screen checkbox. I use my name and my home phone number. That way if someone finds the tablet they can contact me without having to unlock.
Do this for each device user if you have multiple users as I believe what is shown depends on the info about the user that was using it last before it locked.