Mobile tracker for android

Found this app hopping it will be promising it has a function where you can store four contacts to send an sms to incase the sim card gets changed.The concept being incase of theft you can track your phone through sms.Ill give it a go and may be we can see if it realy works.

https://play.google.com/store/apps/details?id=com.admob.nav.mobiletracker&hl=sw