That small percentage of people who can't mark their phones as stolen is not zero but it's small enough for theives not to bother stealing a device which 9 out

That small percentage of people who can't mark their phones as stolen is not zero but it's small enough for theives not to bother stealing a device which 9 out of 10 times is unusable. The upside however of being able to recover a non stolen phone is so much higher.