A few months ago I got my HTC Inspire stolen. I had Wheres my droid installed, but when I tried to track it, it seemed that the thief had already turned off or removed the battery. Same happened to a friends iPhone a week ago, he didn't had any unlock password so the thief probably turned it off very easily.
Now I own a Nexus 4, which has a non-removable battery. I also have an unlock password. But I know there can be ways for a thief to force a turn off and avoid any GPS tracking.
This are my requirements for a stolen phone tracker app:
Activate "phone was stolen" or something like that via SMS (easier to lock the phone from a borrowed phone than having to get home to enter a website and lock it).
Once "phone was stolen" mode is activated, disable all physical buttons (power and volume) and notifications. I believe I would need to root my phone for that, but I don't care.
Once physical buttons are disable, take a picture with the front facing camera the next time the power button is pressed and send it via e-mail.
Bonus: once "phone was stone" mode is activated, change the unlock password for a secundary code previously defined.
I may sound paranoical, but I live in a very unsafe city and I've had 4 phones stolen before (Sony Ericsson T610, Motorola V3, Nokia E63 and HTC Inspire). If you know of any app like this, doesn't matter if its not free, please let me know.