well, when you get the phone, you should look into the 15 digit universal code, and note it down some where, if it ever got stolen or lost, just contact the provider (nokia, LG or what ever you use) and request them to lock your phone, then the phone will become a useless piece of metal....
try to type in
* # 0 6 #
to your phone, and see what happens
also i think if your phone get founded and returned to the police or what ever, they will look into the number too, trying to find the owner etc, not sure if this is true thou